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1// -*- C++ -*-
2//===-------------------------- algorithm ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_ALGORITHM
12#define _LIBCPP_ALGORITHM
13
14/*
15    algorithm synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22template <class InputIterator, class Predicate>
23    bool
24    all_of(InputIterator first, InputIterator last, Predicate pred);
25
26template <class InputIterator, class Predicate>
27    bool
28    any_of(InputIterator first, InputIterator last, Predicate pred);
29
30template <class InputIterator, class Predicate>
31    bool
32    none_of(InputIterator first, InputIterator last, Predicate pred);
33
34template <class InputIterator, class Function>
35    Function
36    for_each(InputIterator first, InputIterator last, Function f);
37
38template <class InputIterator, class T>
39    InputIterator
40    find(InputIterator first, InputIterator last, const T& value);
41
42template <class InputIterator, class Predicate>
43    InputIterator
44    find_if(InputIterator first, InputIterator last, Predicate pred);
45
46template<class InputIterator, class Predicate>
47    InputIterator
48    find_if_not(InputIterator first, InputIterator last, Predicate pred);
49
50template <class ForwardIterator1, class ForwardIterator2>
51    ForwardIterator1
52    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
53             ForwardIterator2 first2, ForwardIterator2 last2);
54
55template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
56    ForwardIterator1
57    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
58             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
59
60template <class ForwardIterator1, class ForwardIterator2>
61    ForwardIterator1
62    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
63                  ForwardIterator2 first2, ForwardIterator2 last2);
64
65template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
66    ForwardIterator1
67    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
68                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
69
70template <class ForwardIterator>
71    ForwardIterator
72    adjacent_find(ForwardIterator first, ForwardIterator last);
73
74template <class ForwardIterator, class BinaryPredicate>
75    ForwardIterator
76    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
77
78template <class InputIterator, class T>
79    typename iterator_traits<InputIterator>::difference_type
80    count(InputIterator first, InputIterator last, const T& value);
81
82template <class InputIterator, class Predicate>
83    typename iterator_traits<InputIterator>::difference_type
84    count_if(InputIterator first, InputIterator last, Predicate pred);
85
86template <class InputIterator1, class InputIterator2>
87    pair<InputIterator1, InputIterator2>
88    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
89
90template <class InputIterator1, class InputIterator2>
91    pair<InputIterator1, InputIterator2>
92    mismatch(InputIterator1 first1, InputIterator1 last1,
93             InputIterator2 first2, InputIterator2 last2); // **C++14**
94
95template <class InputIterator1, class InputIterator2, class BinaryPredicate>
96    pair<InputIterator1, InputIterator2>
97    mismatch(InputIterator1 first1, InputIterator1 last1,
98             InputIterator2 first2, BinaryPredicate pred);
99
100template <class InputIterator1, class InputIterator2, class BinaryPredicate>
101    pair<InputIterator1, InputIterator2>
102    mismatch(InputIterator1 first1, InputIterator1 last1,
103             InputIterator2 first2, InputIterator2 last2,
104             BinaryPredicate pred); // **C++14**
105
106template <class InputIterator1, class InputIterator2>
107    bool
108    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
109
110template <class InputIterator1, class InputIterator2>
111    bool
112    equal(InputIterator1 first1, InputIterator1 last1,
113          InputIterator2 first2, InputIterator2 last2); // **C++14**
114
115template <class InputIterator1, class InputIterator2, class BinaryPredicate>
116    bool
117    equal(InputIterator1 first1, InputIterator1 last1,
118          InputIterator2 first2, BinaryPredicate pred);
119
120template <class InputIterator1, class InputIterator2, class BinaryPredicate>
121    bool
122    equal(InputIterator1 first1, InputIterator1 last1,
123          InputIterator2 first2, InputIterator2 last2,
124          BinaryPredicate pred); // **C++14**
125
126template<class ForwardIterator1, class ForwardIterator2>
127    bool
128    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
129                   ForwardIterator2 first2);
130
131template<class ForwardIterator1, class ForwardIterator2>
132    bool
133    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
134                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
135
136template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
137    bool
138    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
139                   ForwardIterator2 first2, BinaryPredicate pred);
140
141template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
142    bool
143    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
144                   ForwardIterator2 first2, ForwardIterator2 last2,
145                   BinaryPredicate pred);  // **C++14**
146
147template <class ForwardIterator1, class ForwardIterator2>
148    ForwardIterator1
149    search(ForwardIterator1 first1, ForwardIterator1 last1,
150           ForwardIterator2 first2, ForwardIterator2 last2);
151
152template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
153    ForwardIterator1
154    search(ForwardIterator1 first1, ForwardIterator1 last1,
155           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
156
157template <class ForwardIterator, class Size, class T>
158    ForwardIterator
159    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
160
161template <class ForwardIterator, class Size, class T, class BinaryPredicate>
162    ForwardIterator
163    search_n(ForwardIterator first, ForwardIterator last,
164             Size count, const T& value, BinaryPredicate pred);
165
166template <class InputIterator, class OutputIterator>
167    OutputIterator
168    copy(InputIterator first, InputIterator last, OutputIterator result);
169
170template<class InputIterator, class OutputIterator, class Predicate>
171    OutputIterator
172    copy_if(InputIterator first, InputIterator last,
173            OutputIterator result, Predicate pred);
174
175template<class InputIterator, class Size, class OutputIterator>
176    OutputIterator
177    copy_n(InputIterator first, Size n, OutputIterator result);
178
179template <class BidirectionalIterator1, class BidirectionalIterator2>
180    BidirectionalIterator2
181    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
182                  BidirectionalIterator2 result);
183
184template <class ForwardIterator1, class ForwardIterator2>
185    ForwardIterator2
186    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
187
188template <class ForwardIterator1, class ForwardIterator2>
189    void
190    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
191
192template <class InputIterator, class OutputIterator, class UnaryOperation>
193    OutputIterator
194    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
195
196template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
197    OutputIterator
198    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
199              OutputIterator result, BinaryOperation binary_op);
200
201template <class ForwardIterator, class T>
202    void
203    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
204
205template <class ForwardIterator, class Predicate, class T>
206    void
207    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
208
209template <class InputIterator, class OutputIterator, class T>
210    OutputIterator
211    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
212                 const T& old_value, const T& new_value);
213
214template <class InputIterator, class OutputIterator, class Predicate, class T>
215    OutputIterator
216    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
217
218template <class ForwardIterator, class T>
219    void
220    fill(ForwardIterator first, ForwardIterator last, const T& value);
221
222template <class OutputIterator, class Size, class T>
223    OutputIterator
224    fill_n(OutputIterator first, Size n, const T& value);
225
226template <class ForwardIterator, class Generator>
227    void
228    generate(ForwardIterator first, ForwardIterator last, Generator gen);
229
230template <class OutputIterator, class Size, class Generator>
231    OutputIterator
232    generate_n(OutputIterator first, Size n, Generator gen);
233
234template <class ForwardIterator, class T>
235    ForwardIterator
236    remove(ForwardIterator first, ForwardIterator last, const T& value);
237
238template <class ForwardIterator, class Predicate>
239    ForwardIterator
240    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
241
242template <class InputIterator, class OutputIterator, class T>
243    OutputIterator
244    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
245
246template <class InputIterator, class OutputIterator, class Predicate>
247    OutputIterator
248    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
249
250template <class ForwardIterator>
251    ForwardIterator
252    unique(ForwardIterator first, ForwardIterator last);
253
254template <class ForwardIterator, class BinaryPredicate>
255    ForwardIterator
256    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
257
258template <class InputIterator, class OutputIterator>
259    OutputIterator
260    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
261
262template <class InputIterator, class OutputIterator, class BinaryPredicate>
263    OutputIterator
264    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
265
266template <class BidirectionalIterator>
267    void
268    reverse(BidirectionalIterator first, BidirectionalIterator last);
269
270template <class BidirectionalIterator, class OutputIterator>
271    OutputIterator
272    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
273
274template <class ForwardIterator>
275    ForwardIterator
276    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
277
278template <class ForwardIterator, class OutputIterator>
279    OutputIterator
280    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
281
282template <class RandomAccessIterator>
283    void
284    random_shuffle(RandomAccessIterator first, RandomAccessIterator last); // deprecated in C++14
285
286template <class RandomAccessIterator, class RandomNumberGenerator>
287    void
288    random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
289                   RandomNumberGenerator& rand);  // deprecated in C++14
290
291template<class RandomAccessIterator, class UniformRandomNumberGenerator>
292    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
293                 UniformRandomNumberGenerator&& g);
294
295template <class InputIterator, class Predicate>
296    bool
297    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
298
299template <class ForwardIterator, class Predicate>
300    ForwardIterator
301    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
302
303template <class InputIterator, class OutputIterator1,
304          class OutputIterator2, class Predicate>
305    pair<OutputIterator1, OutputIterator2>
306    partition_copy(InputIterator first, InputIterator last,
307                   OutputIterator1 out_true, OutputIterator2 out_false,
308                   Predicate pred);
309
310template <class ForwardIterator, class Predicate>
311    ForwardIterator
312    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
313
314template<class ForwardIterator, class Predicate>
315    ForwardIterator
316    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
317
318template <class ForwardIterator>
319    bool
320    is_sorted(ForwardIterator first, ForwardIterator last);
321
322template <class ForwardIterator, class Compare>
323    bool
324    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
325
326template<class ForwardIterator>
327    ForwardIterator
328    is_sorted_until(ForwardIterator first, ForwardIterator last);
329
330template <class ForwardIterator, class Compare>
331    ForwardIterator
332    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
333
334template <class RandomAccessIterator>
335    void
336    sort(RandomAccessIterator first, RandomAccessIterator last);
337
338template <class RandomAccessIterator, class Compare>
339    void
340    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
341
342template <class RandomAccessIterator>
343    void
344    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
345
346template <class RandomAccessIterator, class Compare>
347    void
348    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
349
350template <class RandomAccessIterator>
351    void
352    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
353
354template <class RandomAccessIterator, class Compare>
355    void
356    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
357
358template <class InputIterator, class RandomAccessIterator>
359    RandomAccessIterator
360    partial_sort_copy(InputIterator first, InputIterator last,
361                      RandomAccessIterator result_first, RandomAccessIterator result_last);
362
363template <class InputIterator, class RandomAccessIterator, class Compare>
364    RandomAccessIterator
365    partial_sort_copy(InputIterator first, InputIterator last,
366                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
367
368template <class RandomAccessIterator>
369    void
370    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
371
372template <class RandomAccessIterator, class Compare>
373    void
374    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
375
376template <class ForwardIterator, class T>
377    ForwardIterator
378    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
379
380template <class ForwardIterator, class T, class Compare>
381    ForwardIterator
382    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
383
384template <class ForwardIterator, class T>
385    ForwardIterator
386    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
387
388template <class ForwardIterator, class T, class Compare>
389    ForwardIterator
390    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
391
392template <class ForwardIterator, class T>
393    pair<ForwardIterator, ForwardIterator>
394    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
395
396template <class ForwardIterator, class T, class Compare>
397    pair<ForwardIterator, ForwardIterator>
398    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
399
400template <class ForwardIterator, class T>
401    bool
402    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
403
404template <class ForwardIterator, class T, class Compare>
405    bool
406    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
407
408template <class InputIterator1, class InputIterator2, class OutputIterator>
409    OutputIterator
410    merge(InputIterator1 first1, InputIterator1 last1,
411          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
412
413template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
414    OutputIterator
415    merge(InputIterator1 first1, InputIterator1 last1,
416          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
417
418template <class BidirectionalIterator>
419    void
420    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
421
422template <class BidirectionalIterator, class Compare>
423    void
424    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
425
426template <class InputIterator1, class InputIterator2>
427    bool
428    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
429
430template <class InputIterator1, class InputIterator2, class Compare>
431    bool
432    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
433
434template <class InputIterator1, class InputIterator2, class OutputIterator>
435    OutputIterator
436    set_union(InputIterator1 first1, InputIterator1 last1,
437              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
438
439template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
440    OutputIterator
441    set_union(InputIterator1 first1, InputIterator1 last1,
442              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
443
444template <class InputIterator1, class InputIterator2, class OutputIterator>
445    OutputIterator
446    set_intersection(InputIterator1 first1, InputIterator1 last1,
447                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
448
449template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
450    OutputIterator
451    set_intersection(InputIterator1 first1, InputIterator1 last1,
452                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
453
454template <class InputIterator1, class InputIterator2, class OutputIterator>
455    OutputIterator
456    set_difference(InputIterator1 first1, InputIterator1 last1,
457                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
458
459template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
460    OutputIterator
461    set_difference(InputIterator1 first1, InputIterator1 last1,
462                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
463
464template <class InputIterator1, class InputIterator2, class OutputIterator>
465    OutputIterator
466    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
467                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
468
469template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
470    OutputIterator
471    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
472                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
473
474template <class RandomAccessIterator>
475    void
476    push_heap(RandomAccessIterator first, RandomAccessIterator last);
477
478template <class RandomAccessIterator, class Compare>
479    void
480    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
481
482template <class RandomAccessIterator>
483    void
484    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
485
486template <class RandomAccessIterator, class Compare>
487    void
488    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
489
490template <class RandomAccessIterator>
491    void
492    make_heap(RandomAccessIterator first, RandomAccessIterator last);
493
494template <class RandomAccessIterator, class Compare>
495    void
496    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
497
498template <class RandomAccessIterator>
499    void
500    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
501
502template <class RandomAccessIterator, class Compare>
503    void
504    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
505
506template <class RandomAccessIterator>
507    bool
508    is_heap(RandomAccessIterator first, RandomAccessiterator last);
509
510template <class RandomAccessIterator, class Compare>
511    bool
512    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
513
514template <class RandomAccessIterator>
515    RandomAccessIterator
516    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
517
518template <class RandomAccessIterator, class Compare>
519    RandomAccessIterator
520    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
521
522template <class ForwardIterator>
523    ForwardIterator
524    min_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
525
526template <class ForwardIterator, class Compare>
527    ForwardIterator
528    min_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
529
530template <class T>
531    const T&
532    min(const T& a, const T& b);  // constexpr in C++14
533
534template <class T, class Compare>
535    const T&
536    min(const T& a, const T& b, Compare comp);  // constexpr in C++14
537
538template<class T>
539    T
540    min(initializer_list<T> t);  // constexpr in C++14
541
542template<class T, class Compare>
543    T
544    min(initializer_list<T> t, Compare comp);  // constexpr in C++14
545
546template <class ForwardIterator>
547    ForwardIterator
548    max_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
549
550template <class ForwardIterator, class Compare>
551    ForwardIterator
552    max_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
553
554template <class T>
555    const T&
556    max(const T& a, const T& b); // constexpr in C++14
557
558template <class T, class Compare>
559    const T&
560    max(const T& a, const T& b, Compare comp);  // constexpr in C++14
561
562template<class T>
563    T
564    max(initializer_list<T> t);  // constexpr in C++14
565
566template<class T, class Compare>
567    T
568    max(initializer_list<T> t, Compare comp);  // constexpr in C++14
569
570template<class ForwardIterator>
571    pair<ForwardIterator, ForwardIterator>
572    minmax_element(ForwardIterator first, ForwardIterator last);   // constexpr in C++14
573
574template<class ForwardIterator, class Compare>
575    pair<ForwardIterator, ForwardIterator>
576    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);   // constexpr in C++14
577
578template<class T>
579    pair<const T&, const T&>
580    minmax(const T& a, const T& b);  // constexpr in C++14
581
582template<class T, class Compare>
583    pair<const T&, const T&>
584    minmax(const T& a, const T& b, Compare comp);  // constexpr in C++14
585
586template<class T>
587    pair<T, T>
588    minmax(initializer_list<T> t);  // constexpr in C++14
589
590template<class T, class Compare>
591    pair<T, T>
592    minmax(initializer_list<T> t, Compare comp);  // constexpr in C++14
593
594template <class InputIterator1, class InputIterator2>
595    bool
596    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
597
598template <class InputIterator1, class InputIterator2, class Compare>
599    bool
600    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
601                            InputIterator2 first2, InputIterator2 last2, Compare comp);
602
603template <class BidirectionalIterator>
604    bool
605    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
606
607template <class BidirectionalIterator, class Compare>
608    bool
609    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
610
611template <class BidirectionalIterator>
612    bool
613    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
614
615template <class BidirectionalIterator, class Compare>
616    bool
617    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
618
619}  // std
620
621*/
622
623#include <__config>
624#include <initializer_list>
625#include <type_traits>
626#include <cstring>
627#include <utility>
628#include <memory>
629#include <iterator>
630#include <cstddef>
631
632#if defined(__IBMCPP__)
633#include "support/ibm/support.h"
634#endif
635#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
636#include "support/win32/support.h"
637#endif
638
639#include <__undef_min_max>
640
641#include <__debug>
642
643#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
644#pragma GCC system_header
645#endif
646
647_LIBCPP_BEGIN_NAMESPACE_STD
648
649// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
650//   * That only works with C++14 and later, and
651//   * We haven't included <functional> here.
652template <class _T1, class _T2 = _T1>
653struct __equal_to
654{
655    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
656    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
657    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
658    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
659};
660
661template <class _T1>
662struct __equal_to<_T1, _T1>
663{
664    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
665    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
666};
667
668template <class _T1>
669struct __equal_to<const _T1, _T1>
670{
671    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
672    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
673};
674
675template <class _T1>
676struct __equal_to<_T1, const _T1>
677{
678    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
679    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
680};
681
682template <class _T1, class _T2 = _T1>
683struct __less
684{
685    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
686    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
687
688    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
689    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
690
691    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
692    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
693
694    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
695    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
696};
697
698template <class _T1>
699struct __less<_T1, _T1>
700{
701    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
702    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
703};
704
705template <class _T1>
706struct __less<const _T1, _T1>
707{
708    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
709    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
710};
711
712template <class _T1>
713struct __less<_T1, const _T1>
714{
715    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
716    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
717};
718
719template <class _Predicate>
720class __negate
721{
722private:
723    _Predicate __p_;
724public:
725    _LIBCPP_INLINE_VISIBILITY __negate() {}
726
727    _LIBCPP_INLINE_VISIBILITY
728    explicit __negate(_Predicate __p) : __p_(__p) {}
729
730    template <class _T1>
731    _LIBCPP_INLINE_VISIBILITY
732    bool operator()(const _T1& __x) {return !__p_(__x);}
733
734    template <class _T1, class _T2>
735    _LIBCPP_INLINE_VISIBILITY
736    bool operator()(const _T1& __x, const _T2& __y) {return !__p_(__x, __y);}
737};
738
739#ifdef _LIBCPP_DEBUG
740
741template <class _Compare>
742struct __debug_less
743{
744    _Compare __comp_;
745    __debug_less(_Compare& __c) : __comp_(__c) {}
746    template <class _Tp, class _Up>
747    bool operator()(const _Tp& __x, const _Up& __y)
748    {
749        bool __r = __comp_(__x, __y);
750        if (__r)
751            _LIBCPP_ASSERT(!__comp_(__y, __x), "Comparator does not induce a strict weak ordering");
752        return __r;
753    }
754};
755
756#endif  // _LIBCPP_DEBUG
757
758// Precondition:  __x != 0
759inline _LIBCPP_INLINE_VISIBILITY
760unsigned
761__ctz(unsigned __x)
762{
763    return static_cast<unsigned>(__builtin_ctz(__x));
764}
765
766inline _LIBCPP_INLINE_VISIBILITY
767unsigned long
768__ctz(unsigned long __x)
769{
770    return static_cast<unsigned long>(__builtin_ctzl(__x));
771}
772
773inline _LIBCPP_INLINE_VISIBILITY
774unsigned long long
775__ctz(unsigned long long __x)
776{
777    return static_cast<unsigned long long>(__builtin_ctzll(__x));
778}
779
780// Precondition:  __x != 0
781inline _LIBCPP_INLINE_VISIBILITY
782unsigned
783__clz(unsigned __x)
784{
785    return static_cast<unsigned>(__builtin_clz(__x));
786}
787
788inline _LIBCPP_INLINE_VISIBILITY
789unsigned long
790__clz(unsigned long __x)
791{
792    return static_cast<unsigned long>(__builtin_clzl (__x));
793}
794
795inline _LIBCPP_INLINE_VISIBILITY
796unsigned long long
797__clz(unsigned long long __x)
798{
799    return static_cast<unsigned long long>(__builtin_clzll(__x));
800}
801
802inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned           __x) {return __builtin_popcount  (__x);}
803inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned      long __x) {return __builtin_popcountl (__x);}
804inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {return __builtin_popcountll(__x);}
805
806// all_of
807
808template <class _InputIterator, class _Predicate>
809inline _LIBCPP_INLINE_VISIBILITY
810bool
811all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
812{
813    for (; __first != __last; ++__first)
814        if (!__pred(*__first))
815            return false;
816    return true;
817}
818
819// any_of
820
821template <class _InputIterator, class _Predicate>
822inline _LIBCPP_INLINE_VISIBILITY
823bool
824any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
825{
826    for (; __first != __last; ++__first)
827        if (__pred(*__first))
828            return true;
829    return false;
830}
831
832// none_of
833
834template <class _InputIterator, class _Predicate>
835inline _LIBCPP_INLINE_VISIBILITY
836bool
837none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
838{
839    for (; __first != __last; ++__first)
840        if (__pred(*__first))
841            return false;
842    return true;
843}
844
845// for_each
846
847template <class _InputIterator, class _Function>
848inline _LIBCPP_INLINE_VISIBILITY
849_Function
850for_each(_InputIterator __first, _InputIterator __last, _Function __f)
851{
852    for (; __first != __last; ++__first)
853        __f(*__first);
854    return _VSTD::move(__f);  // explicitly moved for (emulated) C++03
855}
856
857// find
858
859template <class _InputIterator, class _Tp>
860inline _LIBCPP_INLINE_VISIBILITY
861_InputIterator
862find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
863{
864    for (; __first != __last; ++__first)
865        if (*__first == __value_)
866            break;
867    return __first;
868}
869
870// find_if
871
872template <class _InputIterator, class _Predicate>
873inline _LIBCPP_INLINE_VISIBILITY
874_InputIterator
875find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
876{
877    for (; __first != __last; ++__first)
878        if (__pred(*__first))
879            break;
880    return __first;
881}
882
883// find_if_not
884
885template<class _InputIterator, class _Predicate>
886inline _LIBCPP_INLINE_VISIBILITY
887_InputIterator
888find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
889{
890    for (; __first != __last; ++__first)
891        if (!__pred(*__first))
892            break;
893    return __first;
894}
895
896// find_end
897
898template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
899_ForwardIterator1
900__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
901           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
902           forward_iterator_tag, forward_iterator_tag)
903{
904    // modeled after search algorithm
905    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
906    if (__first2 == __last2)
907        return __r;
908    while (true)
909    {
910        while (true)
911        {
912            if (__first1 == __last1)         // if source exhausted return last correct answer
913                return __r;                  //    (or __last1 if never found)
914            if (__pred(*__first1, *__first2))
915                break;
916            ++__first1;
917        }
918        // *__first1 matches *__first2, now match elements after here
919        _ForwardIterator1 __m1 = __first1;
920        _ForwardIterator2 __m2 = __first2;
921        while (true)
922        {
923            if (++__m2 == __last2)
924            {                         // Pattern exhaused, record answer and search for another one
925                __r = __first1;
926                ++__first1;
927                break;
928            }
929            if (++__m1 == __last1)     // Source exhausted, return last answer
930                return __r;
931            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
932            {
933                ++__first1;
934                break;
935            }  // else there is a match, check next elements
936        }
937    }
938}
939
940template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
941_BidirectionalIterator1
942__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
943           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
944           bidirectional_iterator_tag, bidirectional_iterator_tag)
945{
946    // modeled after search algorithm (in reverse)
947    if (__first2 == __last2)
948        return __last1;  // Everything matches an empty sequence
949    _BidirectionalIterator1 __l1 = __last1;
950    _BidirectionalIterator2 __l2 = __last2;
951    --__l2;
952    while (true)
953    {
954        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
955        while (true)
956        {
957            if (__first1 == __l1)  // return __last1 if no element matches *__first2
958                return __last1;
959            if (__pred(*--__l1, *__l2))
960                break;
961        }
962        // *__l1 matches *__l2, now match elements before here
963        _BidirectionalIterator1 __m1 = __l1;
964        _BidirectionalIterator2 __m2 = __l2;
965        while (true)
966        {
967            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
968                return __m1;
969            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
970                return __last1;
971            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
972            {
973                break;
974            }  // else there is a match, check next elements
975        }
976    }
977}
978
979template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
980_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
981__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
982           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
983           random_access_iterator_tag, random_access_iterator_tag)
984{
985    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
986    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
987    if (__len2 == 0)
988        return __last1;
989    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
990    if (__len1 < __len2)
991        return __last1;
992    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
993    _RandomAccessIterator1 __l1 = __last1;
994    _RandomAccessIterator2 __l2 = __last2;
995    --__l2;
996    while (true)
997    {
998        while (true)
999        {
1000            if (__s == __l1)
1001                return __last1;
1002            if (__pred(*--__l1, *__l2))
1003                break;
1004        }
1005        _RandomAccessIterator1 __m1 = __l1;
1006        _RandomAccessIterator2 __m2 = __l2;
1007        while (true)
1008        {
1009            if (__m2 == __first2)
1010                return __m1;
1011                                 // no need to check range on __m1 because __s guarantees we have enough source
1012            if (!__pred(*--__m1, *--__m2))
1013            {
1014                break;
1015            }
1016        }
1017    }
1018}
1019
1020template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1021inline _LIBCPP_INLINE_VISIBILITY
1022_ForwardIterator1
1023find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1024         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1025{
1026    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
1027                         (__first1, __last1, __first2, __last2, __pred,
1028                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1029                          typename iterator_traits<_ForwardIterator2>::iterator_category());
1030}
1031
1032template <class _ForwardIterator1, class _ForwardIterator2>
1033inline _LIBCPP_INLINE_VISIBILITY
1034_ForwardIterator1
1035find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1036         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1037{
1038    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1039    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1040    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1041}
1042
1043// find_first_of
1044
1045template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1046_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1
1047__find_first_of_ce(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1048              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1049{
1050    for (; __first1 != __last1; ++__first1)
1051        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1052            if (__pred(*__first1, *__j))
1053                return __first1;
1054    return __last1;
1055}
1056
1057
1058template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1059inline _LIBCPP_INLINE_VISIBILITY
1060_ForwardIterator1
1061find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1062              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1063{
1064    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
1065}
1066
1067template <class _ForwardIterator1, class _ForwardIterator2>
1068inline _LIBCPP_INLINE_VISIBILITY
1069_ForwardIterator1
1070find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1071              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1072{
1073    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1074    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1075    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1076}
1077
1078// adjacent_find
1079
1080template <class _ForwardIterator, class _BinaryPredicate>
1081inline _LIBCPP_INLINE_VISIBILITY
1082_ForwardIterator
1083adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
1084{
1085    if (__first != __last)
1086    {
1087        _ForwardIterator __i = __first;
1088        while (++__i != __last)
1089        {
1090            if (__pred(*__first, *__i))
1091                return __first;
1092            __first = __i;
1093        }
1094    }
1095    return __last;
1096}
1097
1098template <class _ForwardIterator>
1099inline _LIBCPP_INLINE_VISIBILITY
1100_ForwardIterator
1101adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
1102{
1103    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1104    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
1105}
1106
1107// count
1108
1109template <class _InputIterator, class _Tp>
1110inline _LIBCPP_INLINE_VISIBILITY
1111typename iterator_traits<_InputIterator>::difference_type
1112count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
1113{
1114    typename iterator_traits<_InputIterator>::difference_type __r(0);
1115    for (; __first != __last; ++__first)
1116        if (*__first == __value_)
1117            ++__r;
1118    return __r;
1119}
1120
1121// count_if
1122
1123template <class _InputIterator, class _Predicate>
1124inline _LIBCPP_INLINE_VISIBILITY
1125typename iterator_traits<_InputIterator>::difference_type
1126count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1127{
1128    typename iterator_traits<_InputIterator>::difference_type __r(0);
1129    for (; __first != __last; ++__first)
1130        if (__pred(*__first))
1131            ++__r;
1132    return __r;
1133}
1134
1135// mismatch
1136
1137template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1138inline _LIBCPP_INLINE_VISIBILITY
1139pair<_InputIterator1, _InputIterator2>
1140mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1141         _InputIterator2 __first2, _BinaryPredicate __pred)
1142{
1143    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1144        if (!__pred(*__first1, *__first2))
1145            break;
1146    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1147}
1148
1149template <class _InputIterator1, class _InputIterator2>
1150inline _LIBCPP_INLINE_VISIBILITY
1151pair<_InputIterator1, _InputIterator2>
1152mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1153{
1154    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1155    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1156    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1157}
1158
1159#if _LIBCPP_STD_VER > 11
1160template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1161inline _LIBCPP_INLINE_VISIBILITY
1162pair<_InputIterator1, _InputIterator2>
1163mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1164         _InputIterator2 __first2, _InputIterator2 __last2,
1165         _BinaryPredicate __pred)
1166{
1167    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1168        if (!__pred(*__first1, *__first2))
1169            break;
1170    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1171}
1172
1173template <class _InputIterator1, class _InputIterator2>
1174inline _LIBCPP_INLINE_VISIBILITY
1175pair<_InputIterator1, _InputIterator2>
1176mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1177         _InputIterator2 __first2, _InputIterator2 __last2)
1178{
1179    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1180    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1181    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1182}
1183#endif
1184
1185// equal
1186
1187template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1188inline _LIBCPP_INLINE_VISIBILITY
1189bool
1190equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
1191{
1192    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1193        if (!__pred(*__first1, *__first2))
1194            return false;
1195    return true;
1196}
1197
1198template <class _InputIterator1, class _InputIterator2>
1199inline _LIBCPP_INLINE_VISIBILITY
1200bool
1201equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1202{
1203    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1204    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1205    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1206}
1207
1208#if _LIBCPP_STD_VER > 11
1209template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
1210inline _LIBCPP_INLINE_VISIBILITY
1211bool
1212__equal(_InputIterator1 __first1, _InputIterator1 __last1,
1213        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
1214        input_iterator_tag, input_iterator_tag )
1215{
1216    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1217        if (!__pred(*__first1, *__first2))
1218            return false;
1219    return __first1 == __last1 && __first2 == __last2;
1220}
1221
1222template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1223inline _LIBCPP_INLINE_VISIBILITY
1224bool
1225__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1226        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1227      random_access_iterator_tag, random_access_iterator_tag )
1228{
1229    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1230        return false;
1231    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
1232                        typename add_lvalue_reference<_BinaryPredicate>::type>
1233                       (__first1, __last1, __first2, __pred );
1234}
1235
1236template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1237inline _LIBCPP_INLINE_VISIBILITY
1238bool
1239equal(_InputIterator1 __first1, _InputIterator1 __last1,
1240      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
1241{
1242    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
1243       (__first1, __last1, __first2, __last2, __pred,
1244        typename iterator_traits<_InputIterator1>::iterator_category(),
1245        typename iterator_traits<_InputIterator2>::iterator_category());
1246}
1247
1248template <class _InputIterator1, class _InputIterator2>
1249inline _LIBCPP_INLINE_VISIBILITY
1250bool
1251equal(_InputIterator1 __first1, _InputIterator1 __last1,
1252      _InputIterator2 __first2, _InputIterator2 __last2)
1253{
1254    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1255    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1256    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
1257        typename iterator_traits<_InputIterator1>::iterator_category(),
1258        typename iterator_traits<_InputIterator2>::iterator_category());
1259}
1260#endif
1261
1262// is_permutation
1263
1264template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1265bool
1266is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1267               _ForwardIterator2 __first2, _BinaryPredicate __pred)
1268{
1269    // shorten sequences as much as possible by lopping of any equal parts
1270    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1271        if (!__pred(*__first1, *__first2))
1272            goto __not_done;
1273    return true;
1274__not_done:
1275    // __first1 != __last1 && *__first1 != *__first2
1276    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1277    _D1 __l1 = _VSTD::distance(__first1, __last1);
1278    if (__l1 == _D1(1))
1279        return false;
1280    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
1281    // For each element in [f1, l1) see if there are the same number of
1282    //    equal elements in [f2, l2)
1283    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1284    {
1285        // Have we already counted the number of *__i in [f1, l1)?
1286        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1287            if (__pred(*__j, *__i))
1288                goto __next_iter;
1289        {
1290            // Count number of *__i in [f2, l2)
1291            _D1 __c2 = 0;
1292            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1293                if (__pred(*__i, *__j))
1294                    ++__c2;
1295            if (__c2 == 0)
1296                return false;
1297            // Count number of *__i in [__i, l1) (we can start with 1)
1298            _D1 __c1 = 1;
1299            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1300                if (__pred(*__i, *__j))
1301                    ++__c1;
1302            if (__c1 != __c2)
1303                return false;
1304        }
1305__next_iter:;
1306    }
1307    return true;
1308}
1309
1310template<class _ForwardIterator1, class _ForwardIterator2>
1311inline _LIBCPP_INLINE_VISIBILITY
1312bool
1313is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1314               _ForwardIterator2 __first2)
1315{
1316    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1317    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1318    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1319}
1320
1321#if _LIBCPP_STD_VER > 11
1322template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1323bool
1324__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1325                 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1326                 _BinaryPredicate __pred,
1327                 forward_iterator_tag, forward_iterator_tag )
1328{
1329    // shorten sequences as much as possible by lopping of any equal parts
1330    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1331        if (!__pred(*__first1, *__first2))
1332            goto __not_done;
1333    return __first1 == __last1 && __first2 == __last2;
1334__not_done:
1335    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
1336    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1337    _D1 __l1 = _VSTD::distance(__first1, __last1);
1338
1339    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
1340    _D2 __l2 = _VSTD::distance(__first2, __last2);
1341    if (__l1 != __l2)
1342        return false;
1343
1344    // For each element in [f1, l1) see if there are the same number of
1345    //    equal elements in [f2, l2)
1346    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1347    {
1348        // Have we already counted the number of *__i in [f1, l1)?
1349        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1350            if (__pred(*__j, *__i))
1351                goto __next_iter;
1352        {
1353            // Count number of *__i in [f2, l2)
1354            _D1 __c2 = 0;
1355            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1356                if (__pred(*__i, *__j))
1357                    ++__c2;
1358            if (__c2 == 0)
1359                return false;
1360            // Count number of *__i in [__i, l1) (we can start with 1)
1361            _D1 __c1 = 1;
1362            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1363                if (__pred(*__i, *__j))
1364                    ++__c1;
1365            if (__c1 != __c2)
1366                return false;
1367        }
1368__next_iter:;
1369    }
1370    return true;
1371}
1372
1373template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1374bool
1375__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
1376               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
1377               _BinaryPredicate __pred,
1378               random_access_iterator_tag, random_access_iterator_tag )
1379{
1380    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1381        return false;
1382    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
1383                                 typename add_lvalue_reference<_BinaryPredicate>::type>
1384                                (__first1, __last1, __first2, __pred );
1385}
1386
1387template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1388inline _LIBCPP_INLINE_VISIBILITY
1389bool
1390is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1391               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1392               _BinaryPredicate __pred )
1393{
1394    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
1395       (__first1, __last1, __first2, __last2, __pred,
1396        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1397        typename iterator_traits<_ForwardIterator2>::iterator_category());
1398}
1399
1400template<class _ForwardIterator1, class _ForwardIterator2>
1401inline _LIBCPP_INLINE_VISIBILITY
1402bool
1403is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1404               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1405{
1406    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1407    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1408    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
1409        __equal_to<__v1, __v2>(),
1410        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1411        typename iterator_traits<_ForwardIterator2>::iterator_category());
1412}
1413#endif
1414
1415// search
1416
1417template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1418_ForwardIterator1
1419__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1420         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1421         forward_iterator_tag, forward_iterator_tag)
1422{
1423    if (__first2 == __last2)
1424        return __first1;  // Everything matches an empty sequence
1425    while (true)
1426    {
1427        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
1428        while (true)
1429        {
1430            if (__first1 == __last1)  // return __last1 if no element matches *__first2
1431                return __last1;
1432            if (__pred(*__first1, *__first2))
1433                break;
1434            ++__first1;
1435        }
1436        // *__first1 matches *__first2, now match elements after here
1437        _ForwardIterator1 __m1 = __first1;
1438        _ForwardIterator2 __m2 = __first2;
1439        while (true)
1440        {
1441            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
1442                return __first1;
1443            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
1444                return __last1;
1445            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
1446            {
1447                ++__first1;
1448                break;
1449            }  // else there is a match, check next elements
1450        }
1451    }
1452}
1453
1454template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1455_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
1456__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1457           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1458           random_access_iterator_tag, random_access_iterator_tag)
1459{
1460    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _D1;
1461    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _D2;
1462    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1463    _D2 __len2 = __last2 - __first2;
1464    if (__len2 == 0)
1465        return __first1;
1466    _D1 __len1 = __last1 - __first1;
1467    if (__len1 < __len2)
1468        return __last1;
1469    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
1470    while (true)
1471    {
1472#if !_LIBCPP_UNROLL_LOOPS
1473        while (true)
1474        {
1475            if (__first1 == __s)
1476                return __last1;
1477            if (__pred(*__first1, *__first2))
1478                break;
1479            ++__first1;
1480        }
1481#else  // !_LIBCPP_UNROLL_LOOPS
1482        for (_D1 __loop_unroll = (__s - __first1) / 4; __loop_unroll > 0; --__loop_unroll)
1483        {
1484            if (__pred(*__first1, *__first2))
1485                goto __phase2;
1486            if (__pred(*++__first1, *__first2))
1487                goto __phase2;
1488            if (__pred(*++__first1, *__first2))
1489                goto __phase2;
1490            if (__pred(*++__first1, *__first2))
1491                goto __phase2;
1492            ++__first1;
1493        }
1494        switch (__s - __first1)
1495        {
1496        case 3:
1497            if (__pred(*__first1, *__first2))
1498                break;
1499            ++__first1;
1500        case 2:
1501            if (__pred(*__first1, *__first2))
1502                break;
1503            ++__first1;
1504        case 1:
1505            if (__pred(*__first1, *__first2))
1506                break;
1507        case 0:
1508            return __last1;
1509        }
1510    __phase2:
1511#endif  // !_LIBCPP_UNROLL_LOOPS
1512        _RandomAccessIterator1 __m1 = __first1;
1513        _RandomAccessIterator2 __m2 = __first2;
1514#if !_LIBCPP_UNROLL_LOOPS
1515         while (true)
1516         {
1517             if (++__m2 == __last2)
1518                 return __first1;
1519             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
1520             if (!__pred(*__m1, *__m2))
1521             {
1522                 ++__first1;
1523                 break;
1524             }
1525         }
1526#else  // !_LIBCPP_UNROLL_LOOPS
1527        ++__m2;
1528        ++__m1;
1529        for (_D2 __loop_unroll = (__last2 - __m2) / 4; __loop_unroll > 0; --__loop_unroll)
1530        {
1531            if (!__pred(*__m1, *__m2))
1532                goto __continue;
1533            if (!__pred(*++__m1, *++__m2))
1534                goto __continue;
1535            if (!__pred(*++__m1, *++__m2))
1536                goto __continue;
1537            if (!__pred(*++__m1, *++__m2))
1538                goto __continue;
1539            ++__m1;
1540            ++__m2;
1541        }
1542        switch (__last2 - __m2)
1543        {
1544        case 3:
1545            if (!__pred(*__m1, *__m2))
1546                break;
1547            ++__m1;
1548            ++__m2;
1549        case 2:
1550            if (!__pred(*__m1, *__m2))
1551                break;
1552            ++__m1;
1553            ++__m2;
1554        case 1:
1555            if (!__pred(*__m1, *__m2))
1556                break;
1557        case 0:
1558            return __first1;
1559        }
1560    __continue:
1561        ++__first1;
1562#endif  // !_LIBCPP_UNROLL_LOOPS
1563    }
1564}
1565
1566template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1567inline _LIBCPP_INLINE_VISIBILITY
1568_ForwardIterator1
1569search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1570       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1571{
1572    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
1573                         (__first1, __last1, __first2, __last2, __pred,
1574                          typename std::iterator_traits<_ForwardIterator1>::iterator_category(),
1575                          typename std::iterator_traits<_ForwardIterator2>::iterator_category());
1576}
1577
1578template <class _ForwardIterator1, class _ForwardIterator2>
1579inline _LIBCPP_INLINE_VISIBILITY
1580_ForwardIterator1
1581search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1582       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1583{
1584    typedef typename std::iterator_traits<_ForwardIterator1>::value_type __v1;
1585    typedef typename std::iterator_traits<_ForwardIterator2>::value_type __v2;
1586    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1587}
1588
1589// search_n
1590
1591template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
1592_ForwardIterator
1593__search_n(_ForwardIterator __first, _ForwardIterator __last,
1594           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
1595{
1596    if (__count <= 0)
1597        return __first;
1598    while (true)
1599    {
1600        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1601        while (true)
1602        {
1603            if (__first == __last)  // return __last if no element matches __value_
1604                return __last;
1605            if (__pred(*__first, __value_))
1606                break;
1607            ++__first;
1608        }
1609        // *__first matches __value_, now match elements after here
1610        _ForwardIterator __m = __first;
1611        _Size __c(0);
1612        while (true)
1613        {
1614            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1615                return __first;
1616            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
1617                return __last;
1618            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1619            {
1620                __first = __m;
1621                ++__first;
1622                break;
1623            }  // else there is a match, check next elements
1624        }
1625    }
1626}
1627
1628template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
1629_RandomAccessIterator
1630__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
1631           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
1632{
1633    if (__count <= 0)
1634        return __first;
1635    _Size __len = static_cast<_Size>(__last - __first);
1636    if (__len < __count)
1637        return __last;
1638    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
1639    while (true)
1640    {
1641        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1642        while (true)
1643        {
1644            if (__first >= __s)  // return __last if no element matches __value_
1645                return __last;
1646            if (__pred(*__first, __value_))
1647                break;
1648            ++__first;
1649        }
1650        // *__first matches __value_, now match elements after here
1651        _RandomAccessIterator __m = __first;
1652        _Size __c(0);
1653        while (true)
1654        {
1655            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1656                return __first;
1657             ++__m;          // no need to check range on __m because __s guarantees we have enough source
1658            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1659            {
1660                __first = __m;
1661                ++__first;
1662                break;
1663            }  // else there is a match, check next elements
1664        }
1665    }
1666}
1667
1668template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
1669inline _LIBCPP_INLINE_VISIBILITY
1670_ForwardIterator
1671search_n(_ForwardIterator __first, _ForwardIterator __last,
1672         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
1673{
1674    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
1675           (__first, __last, __convert_to_integral(__count), __value_, __pred,
1676           typename iterator_traits<_ForwardIterator>::iterator_category());
1677}
1678
1679template <class _ForwardIterator, class _Size, class _Tp>
1680inline _LIBCPP_INLINE_VISIBILITY
1681_ForwardIterator
1682search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
1683{
1684    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1685    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
1686                           __value_, __equal_to<__v, _Tp>());
1687}
1688
1689// copy
1690
1691template <class _Iter>
1692struct __libcpp_is_trivial_iterator
1693{
1694    static const bool value = is_pointer<_Iter>::value;
1695};
1696
1697template <class _Iter>
1698struct __libcpp_is_trivial_iterator<move_iterator<_Iter> >
1699{
1700    static const bool value = is_pointer<_Iter>::value;
1701};
1702
1703template <class _Iter>
1704struct __libcpp_is_trivial_iterator<__wrap_iter<_Iter> >
1705{
1706    static const bool value = is_pointer<_Iter>::value;
1707};
1708
1709template <class _Iter>
1710inline _LIBCPP_INLINE_VISIBILITY
1711_Iter
1712__unwrap_iter(_Iter __i)
1713{
1714    return __i;
1715}
1716
1717template <class _Tp>
1718inline _LIBCPP_INLINE_VISIBILITY
1719typename enable_if
1720<
1721    is_trivially_copy_assignable<_Tp>::value,
1722    _Tp*
1723>::type
1724__unwrap_iter(move_iterator<_Tp*> __i)
1725{
1726    return __i.base();
1727}
1728
1729#if _LIBCPP_DEBUG_LEVEL < 2
1730
1731template <class _Tp>
1732inline _LIBCPP_INLINE_VISIBILITY
1733typename enable_if
1734<
1735    is_trivially_copy_assignable<_Tp>::value,
1736    _Tp*
1737>::type
1738__unwrap_iter(__wrap_iter<_Tp*> __i)
1739{
1740    return __i.base();
1741}
1742
1743#endif  // _LIBCPP_DEBUG_LEVEL < 2
1744
1745template <class _InputIterator, class _OutputIterator>
1746inline _LIBCPP_INLINE_VISIBILITY
1747_OutputIterator
1748__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1749{
1750    for (; __first != __last; ++__first, (void) ++__result)
1751        *__result = *__first;
1752    return __result;
1753}
1754
1755template <class _Tp, class _Up>
1756inline _LIBCPP_INLINE_VISIBILITY
1757typename enable_if
1758<
1759    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1760    is_trivially_copy_assignable<_Up>::value,
1761    _Up*
1762>::type
1763__copy(_Tp* __first, _Tp* __last, _Up* __result)
1764{
1765    const size_t __n = static_cast<size_t>(__last - __first);
1766    if (__n > 0)
1767        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1768    return __result + __n;
1769}
1770
1771template <class _InputIterator, class _OutputIterator>
1772inline _LIBCPP_INLINE_VISIBILITY
1773_OutputIterator
1774copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1775{
1776    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1777}
1778
1779// copy_backward
1780
1781template <class _BidirectionalIterator, class _OutputIterator>
1782inline _LIBCPP_INLINE_VISIBILITY
1783_OutputIterator
1784__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
1785{
1786    while (__first != __last)
1787        *--__result = *--__last;
1788    return __result;
1789}
1790
1791template <class _Tp, class _Up>
1792inline _LIBCPP_INLINE_VISIBILITY
1793typename enable_if
1794<
1795    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1796    is_trivially_copy_assignable<_Up>::value,
1797    _Up*
1798>::type
1799__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
1800{
1801    const size_t __n = static_cast<size_t>(__last - __first);
1802    if (__n > 0)
1803    {
1804        __result -= __n;
1805        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1806    }
1807    return __result;
1808}
1809
1810template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1811inline _LIBCPP_INLINE_VISIBILITY
1812_BidirectionalIterator2
1813copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1814              _BidirectionalIterator2 __result)
1815{
1816    return _VSTD::__copy_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1817}
1818
1819// copy_if
1820
1821template<class _InputIterator, class _OutputIterator, class _Predicate>
1822inline _LIBCPP_INLINE_VISIBILITY
1823_OutputIterator
1824copy_if(_InputIterator __first, _InputIterator __last,
1825        _OutputIterator __result, _Predicate __pred)
1826{
1827    for (; __first != __last; ++__first)
1828    {
1829        if (__pred(*__first))
1830        {
1831            *__result = *__first;
1832            ++__result;
1833        }
1834    }
1835    return __result;
1836}
1837
1838// copy_n
1839
1840template<class _InputIterator, class _Size, class _OutputIterator>
1841inline _LIBCPP_INLINE_VISIBILITY
1842typename enable_if
1843<
1844    __is_input_iterator<_InputIterator>::value &&
1845   !__is_random_access_iterator<_InputIterator>::value,
1846    _OutputIterator
1847>::type
1848copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1849{
1850    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1851    _IntegralSize __n = __orig_n;
1852    if (__n > 0)
1853    {
1854        *__result = *__first;
1855        ++__result;
1856        for (--__n; __n > 0; --__n)
1857        {
1858            ++__first;
1859            *__result = *__first;
1860            ++__result;
1861        }
1862    }
1863    return __result;
1864}
1865
1866template<class _InputIterator, class _Size, class _OutputIterator>
1867inline _LIBCPP_INLINE_VISIBILITY
1868typename enable_if
1869<
1870    __is_random_access_iterator<_InputIterator>::value,
1871    _OutputIterator
1872>::type
1873copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1874{
1875    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1876    _IntegralSize __n = __orig_n;
1877    return _VSTD::copy(__first, __first + __n, __result);
1878}
1879
1880// move
1881
1882template <class _InputIterator, class _OutputIterator>
1883inline _LIBCPP_INLINE_VISIBILITY
1884_OutputIterator
1885__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1886{
1887    for (; __first != __last; ++__first, (void) ++__result)
1888        *__result = _VSTD::move(*__first);
1889    return __result;
1890}
1891
1892template <class _Tp, class _Up>
1893inline _LIBCPP_INLINE_VISIBILITY
1894typename enable_if
1895<
1896    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1897    is_trivially_copy_assignable<_Up>::value,
1898    _Up*
1899>::type
1900__move(_Tp* __first, _Tp* __last, _Up* __result)
1901{
1902    const size_t __n = static_cast<size_t>(__last - __first);
1903    if (__n > 0)
1904        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1905    return __result + __n;
1906}
1907
1908template <class _InputIterator, class _OutputIterator>
1909inline _LIBCPP_INLINE_VISIBILITY
1910_OutputIterator
1911move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1912{
1913    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1914}
1915
1916// move_backward
1917
1918template <class _InputIterator, class _OutputIterator>
1919inline _LIBCPP_INLINE_VISIBILITY
1920_OutputIterator
1921__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1922{
1923    while (__first != __last)
1924        *--__result = _VSTD::move(*--__last);
1925    return __result;
1926}
1927
1928template <class _Tp, class _Up>
1929inline _LIBCPP_INLINE_VISIBILITY
1930typename enable_if
1931<
1932    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1933    is_trivially_copy_assignable<_Up>::value,
1934    _Up*
1935>::type
1936__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
1937{
1938    const size_t __n = static_cast<size_t>(__last - __first);
1939    if (__n > 0)
1940    {
1941        __result -= __n;
1942        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1943    }
1944    return __result;
1945}
1946
1947template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1948inline _LIBCPP_INLINE_VISIBILITY
1949_BidirectionalIterator2
1950move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1951              _BidirectionalIterator2 __result)
1952{
1953    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1954}
1955
1956// iter_swap
1957
1958// moved to <type_traits> for better swap / noexcept support
1959
1960// transform
1961
1962template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
1963inline _LIBCPP_INLINE_VISIBILITY
1964_OutputIterator
1965transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
1966{
1967    for (; __first != __last; ++__first, (void) ++__result)
1968        *__result = __op(*__first);
1969    return __result;
1970}
1971
1972template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
1973inline _LIBCPP_INLINE_VISIBILITY
1974_OutputIterator
1975transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
1976          _OutputIterator __result, _BinaryOperation __binary_op)
1977{
1978    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
1979        *__result = __binary_op(*__first1, *__first2);
1980    return __result;
1981}
1982
1983// replace
1984
1985template <class _ForwardIterator, class _Tp>
1986inline _LIBCPP_INLINE_VISIBILITY
1987void
1988replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
1989{
1990    for (; __first != __last; ++__first)
1991        if (*__first == __old_value)
1992            *__first = __new_value;
1993}
1994
1995// replace_if
1996
1997template <class _ForwardIterator, class _Predicate, class _Tp>
1998inline _LIBCPP_INLINE_VISIBILITY
1999void
2000replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
2001{
2002    for (; __first != __last; ++__first)
2003        if (__pred(*__first))
2004            *__first = __new_value;
2005}
2006
2007// replace_copy
2008
2009template <class _InputIterator, class _OutputIterator, class _Tp>
2010inline _LIBCPP_INLINE_VISIBILITY
2011_OutputIterator
2012replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2013             const _Tp& __old_value, const _Tp& __new_value)
2014{
2015    for (; __first != __last; ++__first, (void) ++__result)
2016        if (*__first == __old_value)
2017            *__result = __new_value;
2018        else
2019            *__result = *__first;
2020    return __result;
2021}
2022
2023// replace_copy_if
2024
2025template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
2026inline _LIBCPP_INLINE_VISIBILITY
2027_OutputIterator
2028replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2029                _Predicate __pred, const _Tp& __new_value)
2030{
2031    for (; __first != __last; ++__first, (void) ++__result)
2032        if (__pred(*__first))
2033            *__result = __new_value;
2034        else
2035            *__result = *__first;
2036    return __result;
2037}
2038
2039// fill_n
2040
2041template <class _OutputIterator, class _Size, class _Tp>
2042inline _LIBCPP_INLINE_VISIBILITY
2043_OutputIterator
2044__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2045{
2046    for (; __n > 0; ++__first, (void) --__n)
2047        *__first = __value_;
2048    return __first;
2049}
2050
2051template <class _Tp, class _Size, class _Up>
2052inline _LIBCPP_INLINE_VISIBILITY
2053typename enable_if
2054<
2055    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
2056    !is_same<_Tp, bool>::value &&
2057    is_integral<_Up>::value && sizeof(_Up) == 1,
2058    _Tp*
2059>::type
2060__fill_n(_Tp* __first, _Size __n,_Up __value_)
2061{
2062    if (__n > 0)
2063        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
2064    return __first + __n;
2065}
2066
2067template <class _OutputIterator, class _Size, class _Tp>
2068inline _LIBCPP_INLINE_VISIBILITY
2069_OutputIterator
2070fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2071{
2072   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
2073}
2074
2075// fill
2076
2077template <class _ForwardIterator, class _Tp>
2078inline _LIBCPP_INLINE_VISIBILITY
2079void
2080__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
2081{
2082    for (; __first != __last; ++__first)
2083        *__first = __value_;
2084}
2085
2086template <class _RandomAccessIterator, class _Tp>
2087inline _LIBCPP_INLINE_VISIBILITY
2088void
2089__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
2090{
2091    _VSTD::fill_n(__first, __last - __first, __value_);
2092}
2093
2094template <class _ForwardIterator, class _Tp>
2095inline _LIBCPP_INLINE_VISIBILITY
2096void
2097fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2098{
2099    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
2100}
2101
2102// generate
2103
2104template <class _ForwardIterator, class _Generator>
2105inline _LIBCPP_INLINE_VISIBILITY
2106void
2107generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
2108{
2109    for (; __first != __last; ++__first)
2110        *__first = __gen();
2111}
2112
2113// generate_n
2114
2115template <class _OutputIterator, class _Size, class _Generator>
2116inline _LIBCPP_INLINE_VISIBILITY
2117_OutputIterator
2118generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
2119{
2120    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
2121    _IntegralSize __n = __orig_n;
2122    for (; __n > 0; ++__first, (void) --__n)
2123        *__first = __gen();
2124    return __first;
2125}
2126
2127// remove
2128
2129template <class _ForwardIterator, class _Tp>
2130_ForwardIterator
2131remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2132{
2133    __first = _VSTD::find(__first, __last, __value_);
2134    if (__first != __last)
2135    {
2136        _ForwardIterator __i = __first;
2137        while (++__i != __last)
2138        {
2139            if (!(*__i == __value_))
2140            {
2141                *__first = _VSTD::move(*__i);
2142                ++__first;
2143            }
2144        }
2145    }
2146    return __first;
2147}
2148
2149// remove_if
2150
2151template <class _ForwardIterator, class _Predicate>
2152_ForwardIterator
2153remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2154{
2155    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
2156                           (__first, __last, __pred);
2157    if (__first != __last)
2158    {
2159        _ForwardIterator __i = __first;
2160        while (++__i != __last)
2161        {
2162            if (!__pred(*__i))
2163            {
2164                *__first = _VSTD::move(*__i);
2165                ++__first;
2166            }
2167        }
2168    }
2169    return __first;
2170}
2171
2172// remove_copy
2173
2174template <class _InputIterator, class _OutputIterator, class _Tp>
2175inline _LIBCPP_INLINE_VISIBILITY
2176_OutputIterator
2177remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
2178{
2179    for (; __first != __last; ++__first)
2180    {
2181        if (!(*__first == __value_))
2182        {
2183            *__result = *__first;
2184            ++__result;
2185        }
2186    }
2187    return __result;
2188}
2189
2190// remove_copy_if
2191
2192template <class _InputIterator, class _OutputIterator, class _Predicate>
2193inline _LIBCPP_INLINE_VISIBILITY
2194_OutputIterator
2195remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
2196{
2197    for (; __first != __last; ++__first)
2198    {
2199        if (!__pred(*__first))
2200        {
2201            *__result = *__first;
2202            ++__result;
2203        }
2204    }
2205    return __result;
2206}
2207
2208// unique
2209
2210template <class _ForwardIterator, class _BinaryPredicate>
2211_ForwardIterator
2212unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
2213{
2214    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
2215                                 (__first, __last, __pred);
2216    if (__first != __last)
2217    {
2218        // ...  a  a  ?  ...
2219        //      f     i
2220        _ForwardIterator __i = __first;
2221        for (++__i; ++__i != __last;)
2222            if (!__pred(*__first, *__i))
2223                *++__first = _VSTD::move(*__i);
2224        ++__first;
2225    }
2226    return __first;
2227}
2228
2229template <class _ForwardIterator>
2230inline _LIBCPP_INLINE_VISIBILITY
2231_ForwardIterator
2232unique(_ForwardIterator __first, _ForwardIterator __last)
2233{
2234    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
2235    return _VSTD::unique(__first, __last, __equal_to<__v>());
2236}
2237
2238// unique_copy
2239
2240template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
2241_OutputIterator
2242__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2243              input_iterator_tag, output_iterator_tag)
2244{
2245    if (__first != __last)
2246    {
2247        typename iterator_traits<_InputIterator>::value_type __t(*__first);
2248        *__result = __t;
2249        ++__result;
2250        while (++__first != __last)
2251        {
2252            if (!__pred(__t, *__first))
2253            {
2254                __t = *__first;
2255                *__result = __t;
2256                ++__result;
2257            }
2258        }
2259    }
2260    return __result;
2261}
2262
2263template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
2264_OutputIterator
2265__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2266              forward_iterator_tag, output_iterator_tag)
2267{
2268    if (__first != __last)
2269    {
2270        _ForwardIterator __i = __first;
2271        *__result = *__i;
2272        ++__result;
2273        while (++__first != __last)
2274        {
2275            if (!__pred(*__i, *__first))
2276            {
2277                *__result = *__first;
2278                ++__result;
2279                __i = __first;
2280            }
2281        }
2282    }
2283    return __result;
2284}
2285
2286template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
2287_ForwardIterator
2288__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
2289              input_iterator_tag, forward_iterator_tag)
2290{
2291    if (__first != __last)
2292    {
2293        *__result = *__first;
2294        while (++__first != __last)
2295            if (!__pred(*__result, *__first))
2296                *++__result = *__first;
2297        ++__result;
2298    }
2299    return __result;
2300}
2301
2302template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
2303inline _LIBCPP_INLINE_VISIBILITY
2304_OutputIterator
2305unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
2306{
2307    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
2308                              (__first, __last, __result, __pred,
2309                               typename iterator_traits<_InputIterator>::iterator_category(),
2310                               typename iterator_traits<_OutputIterator>::iterator_category());
2311}
2312
2313template <class _InputIterator, class _OutputIterator>
2314inline _LIBCPP_INLINE_VISIBILITY
2315_OutputIterator
2316unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
2317{
2318    typedef typename iterator_traits<_InputIterator>::value_type __v;
2319    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
2320}
2321
2322// reverse
2323
2324template <class _BidirectionalIterator>
2325inline _LIBCPP_INLINE_VISIBILITY
2326void
2327__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
2328{
2329    while (__first != __last)
2330    {
2331        if (__first == --__last)
2332            break;
2333        swap(*__first, *__last);
2334        ++__first;
2335    }
2336}
2337
2338template <class _RandomAccessIterator>
2339inline _LIBCPP_INLINE_VISIBILITY
2340void
2341__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
2342{
2343    if (__first != __last)
2344        for (; __first < --__last; ++__first)
2345            swap(*__first, *__last);
2346}
2347
2348template <class _BidirectionalIterator>
2349inline _LIBCPP_INLINE_VISIBILITY
2350void
2351reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
2352{
2353    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
2354}
2355
2356// reverse_copy
2357
2358template <class _BidirectionalIterator, class _OutputIterator>
2359inline _LIBCPP_INLINE_VISIBILITY
2360_OutputIterator
2361reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
2362{
2363    for (; __first != __last; ++__result)
2364        *__result = *--__last;
2365    return __result;
2366}
2367
2368// rotate
2369
2370template <class _ForwardIterator>
2371_ForwardIterator
2372__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
2373{
2374    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
2375    value_type __tmp = _VSTD::move(*__first);
2376    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
2377    *__lm1 = _VSTD::move(__tmp);
2378    return __lm1;
2379}
2380
2381template <class _BidirectionalIterator>
2382_BidirectionalIterator
2383__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
2384{
2385    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
2386    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
2387    value_type __tmp = _VSTD::move(*__lm1);
2388    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
2389    *__first = _VSTD::move(__tmp);
2390    return __fp1;
2391}
2392
2393template <class _ForwardIterator>
2394_ForwardIterator
2395__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2396{
2397    _ForwardIterator __i = __middle;
2398    while (true)
2399    {
2400        swap(*__first, *__i);
2401        ++__first;
2402        if (++__i == __last)
2403            break;
2404        if (__first == __middle)
2405            __middle = __i;
2406    }
2407    _ForwardIterator __r = __first;
2408    if (__first != __middle)
2409    {
2410        __i = __middle;
2411        while (true)
2412        {
2413            swap(*__first, *__i);
2414            ++__first;
2415            if (++__i == __last)
2416            {
2417                if (__first == __middle)
2418                    break;
2419                __i = __middle;
2420            }
2421            else if (__first == __middle)
2422                __middle = __i;
2423        }
2424    }
2425    return __r;
2426}
2427
2428template<typename _Integral>
2429inline _LIBCPP_INLINE_VISIBILITY
2430_Integral
2431__gcd(_Integral __x, _Integral __y)
2432{
2433    do
2434    {
2435        _Integral __t = __x % __y;
2436        __x = __y;
2437        __y = __t;
2438    } while (__y);
2439    return __x;
2440}
2441
2442template<typename _RandomAccessIterator>
2443_RandomAccessIterator
2444__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
2445{
2446    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
2447    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
2448
2449    const difference_type __m1 = __middle - __first;
2450    const difference_type __m2 = __last - __middle;
2451    if (__m1 == __m2)
2452    {
2453        _VSTD::swap_ranges(__first, __middle, __middle);
2454        return __middle;
2455    }
2456    const difference_type __g = _VSTD::__gcd(__m1, __m2);
2457    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
2458    {
2459        value_type __t(_VSTD::move(*--__p));
2460        _RandomAccessIterator __p1 = __p;
2461        _RandomAccessIterator __p2 = __p1 + __m1;
2462        do
2463        {
2464            *__p1 = _VSTD::move(*__p2);
2465            __p1 = __p2;
2466            const difference_type __d = __last - __p2;
2467            if (__m1 < __d)
2468                __p2 += __m1;
2469            else
2470                __p2 = __first + (__m1 - __d);
2471        } while (__p2 != __p);
2472        *__p1 = _VSTD::move(__t);
2473    }
2474    return __first + __m2;
2475}
2476
2477template <class _ForwardIterator>
2478inline _LIBCPP_INLINE_VISIBILITY
2479_ForwardIterator
2480__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
2481         _VSTD::forward_iterator_tag)
2482{
2483    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
2484    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2485    {
2486        if (_VSTD::next(__first) == __middle)
2487            return _VSTD::__rotate_left(__first, __last);
2488    }
2489    return _VSTD::__rotate_forward(__first, __middle, __last);
2490}
2491
2492template <class _BidirectionalIterator>
2493inline _LIBCPP_INLINE_VISIBILITY
2494_BidirectionalIterator
2495__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
2496         _VSTD::bidirectional_iterator_tag)
2497{
2498    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
2499    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2500    {
2501        if (_VSTD::next(__first) == __middle)
2502            return _VSTD::__rotate_left(__first, __last);
2503        if (_VSTD::next(__middle) == __last)
2504            return _VSTD::__rotate_right(__first, __last);
2505    }
2506    return _VSTD::__rotate_forward(__first, __middle, __last);
2507}
2508
2509template <class _RandomAccessIterator>
2510inline _LIBCPP_INLINE_VISIBILITY
2511_RandomAccessIterator
2512__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
2513         _VSTD::random_access_iterator_tag)
2514{
2515    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
2516    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2517    {
2518        if (_VSTD::next(__first) == __middle)
2519            return _VSTD::__rotate_left(__first, __last);
2520        if (_VSTD::next(__middle) == __last)
2521            return _VSTD::__rotate_right(__first, __last);
2522        return _VSTD::__rotate_gcd(__first, __middle, __last);
2523    }
2524    return _VSTD::__rotate_forward(__first, __middle, __last);
2525}
2526
2527template <class _ForwardIterator>
2528inline _LIBCPP_INLINE_VISIBILITY
2529_ForwardIterator
2530rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2531{
2532    if (__first == __middle)
2533        return __last;
2534    if (__middle == __last)
2535        return __first;
2536    return _VSTD::__rotate(__first, __middle, __last,
2537                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
2538}
2539
2540// rotate_copy
2541
2542template <class _ForwardIterator, class _OutputIterator>
2543inline _LIBCPP_INLINE_VISIBILITY
2544_OutputIterator
2545rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
2546{
2547    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
2548}
2549
2550// min_element
2551
2552template <class _ForwardIterator, class _Compare>
2553inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2554_ForwardIterator
2555min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2556{
2557    if (__first != __last)
2558    {
2559        _ForwardIterator __i = __first;
2560        while (++__i != __last)
2561            if (__comp(*__i, *__first))
2562                __first = __i;
2563    }
2564    return __first;
2565}
2566
2567template <class _ForwardIterator>
2568inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2569_ForwardIterator
2570min_element(_ForwardIterator __first, _ForwardIterator __last)
2571{
2572    return _VSTD::min_element(__first, __last,
2573              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2574}
2575
2576// min
2577
2578template <class _Tp, class _Compare>
2579inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2580const _Tp&
2581min(const _Tp& __a, const _Tp& __b, _Compare __comp)
2582{
2583    return __comp(__b, __a) ? __b : __a;
2584}
2585
2586template <class _Tp>
2587inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2588const _Tp&
2589min(const _Tp& __a, const _Tp& __b)
2590{
2591    return _VSTD::min(__a, __b, __less<_Tp>());
2592}
2593
2594#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2595
2596template<class _Tp, class _Compare>
2597inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2598_Tp
2599min(initializer_list<_Tp> __t, _Compare __comp)
2600{
2601    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
2602}
2603
2604template<class _Tp>
2605inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2606_Tp
2607min(initializer_list<_Tp> __t)
2608{
2609    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
2610}
2611
2612#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2613
2614// max_element
2615
2616template <class _ForwardIterator, class _Compare>
2617inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2618_ForwardIterator
2619max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2620{
2621    if (__first != __last)
2622    {
2623        _ForwardIterator __i = __first;
2624        while (++__i != __last)
2625            if (__comp(*__first, *__i))
2626                __first = __i;
2627    }
2628    return __first;
2629}
2630
2631
2632template <class _ForwardIterator>
2633inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2634_ForwardIterator
2635max_element(_ForwardIterator __first, _ForwardIterator __last)
2636{
2637    return _VSTD::max_element(__first, __last,
2638              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2639}
2640
2641// max
2642
2643template <class _Tp, class _Compare>
2644inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2645const _Tp&
2646max(const _Tp& __a, const _Tp& __b, _Compare __comp)
2647{
2648    return __comp(__a, __b) ? __b : __a;
2649}
2650
2651template <class _Tp>
2652inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2653const _Tp&
2654max(const _Tp& __a, const _Tp& __b)
2655{
2656    return _VSTD::max(__a, __b, __less<_Tp>());
2657}
2658
2659#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2660
2661template<class _Tp, class _Compare>
2662inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2663_Tp
2664max(initializer_list<_Tp> __t, _Compare __comp)
2665{
2666    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
2667}
2668
2669template<class _Tp>
2670inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2671_Tp
2672max(initializer_list<_Tp> __t)
2673{
2674    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
2675}
2676
2677#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2678
2679// minmax_element
2680
2681template <class _ForwardIterator, class _Compare>
2682_LIBCPP_CONSTEXPR_AFTER_CXX11
2683std::pair<_ForwardIterator, _ForwardIterator>
2684minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2685{
2686  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
2687  if (__first != __last)
2688  {
2689      if (++__first != __last)
2690      {
2691          if (__comp(*__first, *__result.first))
2692              __result.first = __first;
2693          else
2694              __result.second = __first;
2695          while (++__first != __last)
2696          {
2697              _ForwardIterator __i = __first;
2698              if (++__first == __last)
2699              {
2700                  if (__comp(*__i, *__result.first))
2701                      __result.first = __i;
2702                  else if (!__comp(*__i, *__result.second))
2703                      __result.second = __i;
2704                  break;
2705              }
2706              else
2707              {
2708                  if (__comp(*__first, *__i))
2709                  {
2710                      if (__comp(*__first, *__result.first))
2711                          __result.first = __first;
2712                      if (!__comp(*__i, *__result.second))
2713                          __result.second = __i;
2714                  }
2715                  else
2716                  {
2717                      if (__comp(*__i, *__result.first))
2718                          __result.first = __i;
2719                      if (!__comp(*__first, *__result.second))
2720                          __result.second = __first;
2721                  }
2722              }
2723          }
2724      }
2725  }
2726  return __result;
2727}
2728
2729template <class _ForwardIterator>
2730inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2731std::pair<_ForwardIterator, _ForwardIterator>
2732minmax_element(_ForwardIterator __first, _ForwardIterator __last)
2733{
2734    return _VSTD::minmax_element(__first, __last,
2735              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2736}
2737
2738// minmax
2739
2740template<class _Tp, class _Compare>
2741inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2742pair<const _Tp&, const _Tp&>
2743minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
2744{
2745    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
2746                              pair<const _Tp&, const _Tp&>(__a, __b);
2747}
2748
2749template<class _Tp>
2750inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2751pair<const _Tp&, const _Tp&>
2752minmax(const _Tp& __a, const _Tp& __b)
2753{
2754    return _VSTD::minmax(__a, __b, __less<_Tp>());
2755}
2756
2757#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2758
2759template<class _Tp, class _Compare>
2760inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2761pair<_Tp, _Tp>
2762minmax(initializer_list<_Tp> __t, _Compare __comp)
2763{
2764    typedef typename initializer_list<_Tp>::const_iterator _Iter;
2765    _Iter __first = __t.begin();
2766    _Iter __last  = __t.end();
2767    std::pair<_Tp, _Tp> __result(*__first, *__first);
2768
2769    ++__first;
2770    if (__t.size() % 2 == 0)
2771    {
2772        if (__comp(*__first,  __result.first))
2773            __result.first  = *__first;
2774        else
2775            __result.second = *__first;
2776        ++__first;
2777    }
2778
2779    while (__first != __last)
2780    {
2781        _Tp __prev = *__first++;
2782        if (__comp(*__first, __prev)) {
2783            if ( __comp(*__first, __result.first)) __result.first  = *__first;
2784            if (!__comp(__prev, __result.second))  __result.second = __prev;
2785            }
2786        else {
2787            if ( __comp(__prev, __result.first))    __result.first  = __prev;
2788            if (!__comp(*__first, __result.second)) __result.second = *__first;
2789            }
2790
2791        __first++;
2792    }
2793    return __result;
2794}
2795
2796template<class _Tp>
2797inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2798pair<_Tp, _Tp>
2799minmax(initializer_list<_Tp> __t)
2800{
2801    return _VSTD::minmax(__t, __less<_Tp>());
2802}
2803
2804#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2805
2806// random_shuffle
2807
2808// __independent_bits_engine
2809
2810template <unsigned long long _Xp, size_t _Rp>
2811struct __log2_imp
2812{
2813    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
2814                                           : __log2_imp<_Xp, _Rp - 1>::value;
2815};
2816
2817template <unsigned long long _Xp>
2818struct __log2_imp<_Xp, 0>
2819{
2820    static const size_t value = 0;
2821};
2822
2823template <size_t _Rp>
2824struct __log2_imp<0, _Rp>
2825{
2826    static const size_t value = _Rp + 1;
2827};
2828
2829template <class _UI, _UI _Xp>
2830struct __log2
2831{
2832    static const size_t value = __log2_imp<_Xp,
2833                                         sizeof(_UI) * __CHAR_BIT__ - 1>::value;
2834};
2835
2836template<class _Engine, class _UIntType>
2837class __independent_bits_engine
2838{
2839public:
2840    // types
2841    typedef _UIntType result_type;
2842
2843private:
2844    typedef typename _Engine::result_type _Engine_result_type;
2845    typedef typename conditional
2846        <
2847            sizeof(_Engine_result_type) <= sizeof(result_type),
2848                result_type,
2849                _Engine_result_type
2850        >::type _Working_result_type;
2851
2852    _Engine& __e_;
2853    size_t __w_;
2854    size_t __w0_;
2855    size_t __n_;
2856    size_t __n0_;
2857    _Working_result_type __y0_;
2858    _Working_result_type __y1_;
2859    _Engine_result_type __mask0_;
2860    _Engine_result_type __mask1_;
2861
2862#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2863    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2864                                          + _Working_result_type(1);
2865#else
2866    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2867                                                      + _Working_result_type(1);
2868#endif
2869    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2870    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2871    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2872
2873public:
2874    // constructors and seeding functions
2875    __independent_bits_engine(_Engine& __e, size_t __w);
2876
2877    // generating functions
2878    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2879
2880private:
2881    result_type __eval(false_type);
2882    result_type __eval(true_type);
2883};
2884
2885template<class _Engine, class _UIntType>
2886__independent_bits_engine<_Engine, _UIntType>
2887    ::__independent_bits_engine(_Engine& __e, size_t __w)
2888        : __e_(__e),
2889          __w_(__w)
2890{
2891    __n_ = __w_ / __m + (__w_ % __m != 0);
2892    __w0_ = __w_ / __n_;
2893    if (_Rp == 0)
2894        __y0_ = _Rp;
2895    else if (__w0_ < _WDt)
2896        __y0_ = (_Rp >> __w0_) << __w0_;
2897    else
2898        __y0_ = 0;
2899    if (_Rp - __y0_ > __y0_ / __n_)
2900    {
2901        ++__n_;
2902        __w0_ = __w_ / __n_;
2903        if (__w0_ < _WDt)
2904            __y0_ = (_Rp >> __w0_) << __w0_;
2905        else
2906            __y0_ = 0;
2907    }
2908    __n0_ = __n_ - __w_ % __n_;
2909    if (__w0_ < _WDt - 1)
2910        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
2911    else
2912        __y1_ = 0;
2913    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
2914                          _Engine_result_type(0);
2915    __mask1_ = __w0_ < _EDt - 1 ?
2916                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
2917                               _Engine_result_type(~0);
2918}
2919
2920template<class _Engine, class _UIntType>
2921inline
2922_UIntType
2923__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
2924{
2925    return static_cast<result_type>(__e_() & __mask0_);
2926}
2927
2928template<class _Engine, class _UIntType>
2929_UIntType
2930__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
2931{
2932    result_type _Sp = 0;
2933    for (size_t __k = 0; __k < __n0_; ++__k)
2934    {
2935        _Engine_result_type __u;
2936        do
2937        {
2938            __u = __e_() - _Engine::min();
2939        } while (__u >= __y0_);
2940        if (__w0_ < _WDt)
2941            _Sp <<= __w0_;
2942        else
2943            _Sp = 0;
2944        _Sp += __u & __mask0_;
2945    }
2946    for (size_t __k = __n0_; __k < __n_; ++__k)
2947    {
2948        _Engine_result_type __u;
2949        do
2950        {
2951            __u = __e_() - _Engine::min();
2952        } while (__u >= __y1_);
2953        if (__w0_ < _WDt - 1)
2954            _Sp <<= __w0_ + 1;
2955        else
2956            _Sp = 0;
2957        _Sp += __u & __mask1_;
2958    }
2959    return _Sp;
2960}
2961
2962// uniform_int_distribution
2963
2964template<class _IntType = int>
2965class uniform_int_distribution
2966{
2967public:
2968    // types
2969    typedef _IntType result_type;
2970
2971    class param_type
2972    {
2973        result_type __a_;
2974        result_type __b_;
2975    public:
2976        typedef uniform_int_distribution distribution_type;
2977
2978        explicit param_type(result_type __a = 0,
2979                            result_type __b = numeric_limits<result_type>::max())
2980            : __a_(__a), __b_(__b) {}
2981
2982        result_type a() const {return __a_;}
2983        result_type b() const {return __b_;}
2984
2985        friend bool operator==(const param_type& __x, const param_type& __y)
2986            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
2987        friend bool operator!=(const param_type& __x, const param_type& __y)
2988            {return !(__x == __y);}
2989    };
2990
2991private:
2992    param_type __p_;
2993
2994public:
2995    // constructors and reset functions
2996    explicit uniform_int_distribution(result_type __a = 0,
2997                                      result_type __b = numeric_limits<result_type>::max())
2998        : __p_(param_type(__a, __b)) {}
2999    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
3000    void reset() {}
3001
3002    // generating functions
3003    template<class _URNG> result_type operator()(_URNG& __g)
3004        {return (*this)(__g, __p_);}
3005    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3006
3007    // property functions
3008    result_type a() const {return __p_.a();}
3009    result_type b() const {return __p_.b();}
3010
3011    param_type param() const {return __p_;}
3012    void param(const param_type& __p) {__p_ = __p;}
3013
3014    result_type min() const {return a();}
3015    result_type max() const {return b();}
3016
3017    friend bool operator==(const uniform_int_distribution& __x,
3018                           const uniform_int_distribution& __y)
3019        {return __x.__p_ == __y.__p_;}
3020    friend bool operator!=(const uniform_int_distribution& __x,
3021                           const uniform_int_distribution& __y)
3022            {return !(__x == __y);}
3023};
3024
3025template<class _IntType>
3026template<class _URNG>
3027typename uniform_int_distribution<_IntType>::result_type
3028uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
3029{
3030    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
3031                                            uint32_t, uint64_t>::type _UIntType;
3032    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
3033    if (_Rp == 1)
3034        return __p.a();
3035    const size_t _Dt = numeric_limits<_UIntType>::digits;
3036    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
3037    if (_Rp == 0)
3038        return static_cast<result_type>(_Eng(__g, _Dt)());
3039    size_t __w = _Dt - __clz(_Rp) - 1;
3040    if ((_Rp & (std::numeric_limits<_UIntType>::max() >> (_Dt - __w))) != 0)
3041        ++__w;
3042    _Eng __e(__g, __w);
3043    _UIntType __u;
3044    do
3045    {
3046        __u = __e();
3047    } while (__u >= _Rp);
3048    return static_cast<result_type>(__u + __p.a());
3049}
3050
3051class _LIBCPP_TYPE_VIS __rs_default;
3052
3053_LIBCPP_FUNC_VIS __rs_default __rs_get();
3054
3055class _LIBCPP_TYPE_VIS __rs_default
3056{
3057    static unsigned __c_;
3058
3059    __rs_default();
3060public:
3061    typedef uint_fast32_t result_type;
3062
3063    static const result_type _Min = 0;
3064    static const result_type _Max = 0xFFFFFFFF;
3065
3066    __rs_default(const __rs_default&);
3067    ~__rs_default();
3068
3069    result_type operator()();
3070
3071    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
3072    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
3073
3074    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
3075};
3076
3077_LIBCPP_FUNC_VIS __rs_default __rs_get();
3078
3079template <class _RandomAccessIterator>
3080void
3081random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
3082{
3083    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3084    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3085    typedef typename _Dp::param_type _Pp;
3086    difference_type __d = __last - __first;
3087    if (__d > 1)
3088    {
3089        _Dp __uid;
3090        __rs_default __g = __rs_get();
3091        for (--__last, --__d; __first < __last; ++__first, --__d)
3092        {
3093            difference_type __i = __uid(__g, _Pp(0, __d));
3094            if (__i != difference_type(0))
3095                swap(*__first, *(__first + __i));
3096        }
3097    }
3098}
3099
3100template <class _RandomAccessIterator, class _RandomNumberGenerator>
3101void
3102random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3103#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3104               _RandomNumberGenerator&& __rand)
3105#else
3106               _RandomNumberGenerator& __rand)
3107#endif
3108{
3109    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3110    difference_type __d = __last - __first;
3111    if (__d > 1)
3112    {
3113        for (--__last; __first < __last; ++__first, --__d)
3114        {
3115            difference_type __i = __rand(__d);
3116            swap(*__first, *(__first + __i));
3117        }
3118    }
3119}
3120
3121template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
3122    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3123#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3124                 _UniformRandomNumberGenerator&& __g)
3125#else
3126                 _UniformRandomNumberGenerator& __g)
3127#endif
3128{
3129    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3130    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3131    typedef typename _Dp::param_type _Pp;
3132    difference_type __d = __last - __first;
3133    if (__d > 1)
3134    {
3135        _Dp __uid;
3136        for (--__last, --__d; __first < __last; ++__first, --__d)
3137        {
3138            difference_type __i = __uid(__g, _Pp(0, __d));
3139            if (__i != difference_type(0))
3140                swap(*__first, *(__first + __i));
3141        }
3142    }
3143}
3144
3145template <class _InputIterator, class _Predicate>
3146bool
3147is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3148{
3149    for (; __first != __last; ++__first)
3150        if (!__pred(*__first))
3151            break;
3152    if ( __first == __last )
3153        return true;
3154    ++__first;
3155    for (; __first != __last; ++__first)
3156        if (__pred(*__first))
3157            return false;
3158    return true;
3159}
3160
3161// partition
3162
3163template <class _Predicate, class _ForwardIterator>
3164_ForwardIterator
3165__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
3166{
3167    while (true)
3168    {
3169        if (__first == __last)
3170            return __first;
3171        if (!__pred(*__first))
3172            break;
3173        ++__first;
3174    }
3175    for (_ForwardIterator __p = __first; ++__p != __last;)
3176    {
3177        if (__pred(*__p))
3178        {
3179            swap(*__first, *__p);
3180            ++__first;
3181        }
3182    }
3183    return __first;
3184}
3185
3186template <class _Predicate, class _BidirectionalIterator>
3187_BidirectionalIterator
3188__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3189            bidirectional_iterator_tag)
3190{
3191    while (true)
3192    {
3193        while (true)
3194        {
3195            if (__first == __last)
3196                return __first;
3197            if (!__pred(*__first))
3198                break;
3199            ++__first;
3200        }
3201        do
3202        {
3203            if (__first == --__last)
3204                return __first;
3205        } while (!__pred(*__last));
3206        swap(*__first, *__last);
3207        ++__first;
3208    }
3209}
3210
3211template <class _ForwardIterator, class _Predicate>
3212inline _LIBCPP_INLINE_VISIBILITY
3213_ForwardIterator
3214partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3215{
3216    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
3217                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3218}
3219
3220// partition_copy
3221
3222template <class _InputIterator, class _OutputIterator1,
3223          class _OutputIterator2, class _Predicate>
3224pair<_OutputIterator1, _OutputIterator2>
3225partition_copy(_InputIterator __first, _InputIterator __last,
3226               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
3227               _Predicate __pred)
3228{
3229    for (; __first != __last; ++__first)
3230    {
3231        if (__pred(*__first))
3232        {
3233            *__out_true = *__first;
3234            ++__out_true;
3235        }
3236        else
3237        {
3238            *__out_false = *__first;
3239            ++__out_false;
3240        }
3241    }
3242    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
3243}
3244
3245// partition_point
3246
3247template<class _ForwardIterator, class _Predicate>
3248_ForwardIterator
3249partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3250{
3251    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3252    difference_type __len = _VSTD::distance(__first, __last);
3253    while (__len != 0)
3254    {
3255        difference_type __l2 = __len / 2;
3256        _ForwardIterator __m = __first;
3257        _VSTD::advance(__m, __l2);
3258        if (__pred(*__m))
3259        {
3260            __first = ++__m;
3261            __len -= __l2 + 1;
3262        }
3263        else
3264            __len = __l2;
3265    }
3266    return __first;
3267}
3268
3269// stable_partition
3270
3271template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
3272_ForwardIterator
3273__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3274                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
3275{
3276    // *__first is known to be false
3277    // __len >= 1
3278    if (__len == 1)
3279        return __first;
3280    if (__len == 2)
3281    {
3282        _ForwardIterator __m = __first;
3283        if (__pred(*++__m))
3284        {
3285            swap(*__first, *__m);
3286            return __m;
3287        }
3288        return __first;
3289    }
3290    if (__len <= __p.second)
3291    {   // The buffer is big enough to use
3292        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3293        __destruct_n __d(0);
3294        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3295        // Move the falses into the temporary buffer, and the trues to the front of the line
3296        // Update __first to always point to the end of the trues
3297        value_type* __t = __p.first;
3298        ::new(__t) value_type(_VSTD::move(*__first));
3299        __d.__incr((value_type*)0);
3300        ++__t;
3301        _ForwardIterator __i = __first;
3302        while (++__i != __last)
3303        {
3304            if (__pred(*__i))
3305            {
3306                *__first = _VSTD::move(*__i);
3307                ++__first;
3308            }
3309            else
3310            {
3311                ::new(__t) value_type(_VSTD::move(*__i));
3312                __d.__incr((value_type*)0);
3313                ++__t;
3314            }
3315        }
3316        // All trues now at start of range, all falses in buffer
3317        // Move falses back into range, but don't mess up __first which points to first false
3318        __i = __first;
3319        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3320            *__i = _VSTD::move(*__t2);
3321        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3322        return __first;
3323    }
3324    // Else not enough buffer, do in place
3325    // __len >= 3
3326    _ForwardIterator __m = __first;
3327    _Distance __len2 = __len / 2;  // __len2 >= 2
3328    _VSTD::advance(__m, __len2);
3329    // recurse on [__first, __m), *__first know to be false
3330    // F?????????????????
3331    // f       m         l
3332    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3333    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
3334    // TTTFFFFF??????????
3335    // f  ff   m         l
3336    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3337    _ForwardIterator __m1 = __m;
3338    _ForwardIterator __second_false = __last;
3339    _Distance __len_half = __len - __len2;
3340    while (__pred(*__m1))
3341    {
3342        if (++__m1 == __last)
3343            goto __second_half_done;
3344        --__len_half;
3345    }
3346    // TTTFFFFFTTTF??????
3347    // f  ff   m  m1     l
3348    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
3349__second_half_done:
3350    // TTTFFFFFTTTTTFFFFF
3351    // f  ff   m    sf   l
3352    return _VSTD::rotate(__first_false, __m, __second_false);
3353    // TTTTTTTTFFFFFFFFFF
3354    //         |
3355}
3356
3357struct __return_temporary_buffer
3358{
3359    template <class _Tp>
3360    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
3361};
3362
3363template <class _Predicate, class _ForwardIterator>
3364_ForwardIterator
3365__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3366                   forward_iterator_tag)
3367{
3368    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
3369    // Either prove all true and return __first or point to first false
3370    while (true)
3371    {
3372        if (__first == __last)
3373            return __first;
3374        if (!__pred(*__first))
3375            break;
3376        ++__first;
3377    }
3378    // We now have a reduced range [__first, __last)
3379    // *__first is known to be false
3380    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3381    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3382    difference_type __len = _VSTD::distance(__first, __last);
3383    pair<value_type*, ptrdiff_t> __p(0, 0);
3384    unique_ptr<value_type, __return_temporary_buffer> __h;
3385    if (__len >= __alloc_limit)
3386    {
3387        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3388        __h.reset(__p.first);
3389    }
3390    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3391                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
3392}
3393
3394template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
3395_BidirectionalIterator
3396__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3397                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
3398{
3399    // *__first is known to be false
3400    // *__last is known to be true
3401    // __len >= 2
3402    if (__len == 2)
3403    {
3404        swap(*__first, *__last);
3405        return __last;
3406    }
3407    if (__len == 3)
3408    {
3409        _BidirectionalIterator __m = __first;
3410        if (__pred(*++__m))
3411        {
3412            swap(*__first, *__m);
3413            swap(*__m, *__last);
3414            return __last;
3415        }
3416        swap(*__m, *__last);
3417        swap(*__first, *__m);
3418        return __m;
3419    }
3420    if (__len <= __p.second)
3421    {   // The buffer is big enough to use
3422        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3423        __destruct_n __d(0);
3424        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3425        // Move the falses into the temporary buffer, and the trues to the front of the line
3426        // Update __first to always point to the end of the trues
3427        value_type* __t = __p.first;
3428        ::new(__t) value_type(_VSTD::move(*__first));
3429        __d.__incr((value_type*)0);
3430        ++__t;
3431        _BidirectionalIterator __i = __first;
3432        while (++__i != __last)
3433        {
3434            if (__pred(*__i))
3435            {
3436                *__first = _VSTD::move(*__i);
3437                ++__first;
3438            }
3439            else
3440            {
3441                ::new(__t) value_type(_VSTD::move(*__i));
3442                __d.__incr((value_type*)0);
3443                ++__t;
3444            }
3445        }
3446        // move *__last, known to be true
3447        *__first = _VSTD::move(*__i);
3448        __i = ++__first;
3449        // All trues now at start of range, all falses in buffer
3450        // Move falses back into range, but don't mess up __first which points to first false
3451        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3452            *__i = _VSTD::move(*__t2);
3453        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3454        return __first;
3455    }
3456    // Else not enough buffer, do in place
3457    // __len >= 4
3458    _BidirectionalIterator __m = __first;
3459    _Distance __len2 = __len / 2;  // __len2 >= 2
3460    _VSTD::advance(__m, __len2);
3461    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
3462    // F????????????????T
3463    // f       m        l
3464    _BidirectionalIterator __m1 = __m;
3465    _BidirectionalIterator __first_false = __first;
3466    _Distance __len_half = __len2;
3467    while (!__pred(*--__m1))
3468    {
3469        if (__m1 == __first)
3470            goto __first_half_done;
3471        --__len_half;
3472    }
3473    // F???TFFF?????????T
3474    // f   m1  m        l
3475    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3476    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
3477__first_half_done:
3478    // TTTFFFFF?????????T
3479    // f  ff   m        l
3480    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3481    __m1 = __m;
3482    _BidirectionalIterator __second_false = __last;
3483    ++__second_false;
3484    __len_half = __len - __len2;
3485    while (__pred(*__m1))
3486    {
3487        if (++__m1 == __last)
3488            goto __second_half_done;
3489        --__len_half;
3490    }
3491    // TTTFFFFFTTTF?????T
3492    // f  ff   m  m1    l
3493    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
3494__second_half_done:
3495    // TTTFFFFFTTTTTFFFFF
3496    // f  ff   m    sf  l
3497    return _VSTD::rotate(__first_false, __m, __second_false);
3498    // TTTTTTTTFFFFFFFFFF
3499    //         |
3500}
3501
3502template <class _Predicate, class _BidirectionalIterator>
3503_BidirectionalIterator
3504__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3505                   bidirectional_iterator_tag)
3506{
3507    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
3508    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3509    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
3510    // Either prove all true and return __first or point to first false
3511    while (true)
3512    {
3513        if (__first == __last)
3514            return __first;
3515        if (!__pred(*__first))
3516            break;
3517        ++__first;
3518    }
3519    // __first points to first false, everything prior to __first is already set.
3520    // Either prove [__first, __last) is all false and return __first, or point __last to last true
3521    do
3522    {
3523        if (__first == --__last)
3524            return __first;
3525    } while (!__pred(*__last));
3526    // We now have a reduced range [__first, __last]
3527    // *__first is known to be false
3528    // *__last is known to be true
3529    // __len >= 2
3530    difference_type __len = _VSTD::distance(__first, __last) + 1;
3531    pair<value_type*, ptrdiff_t> __p(0, 0);
3532    unique_ptr<value_type, __return_temporary_buffer> __h;
3533    if (__len >= __alloc_limit)
3534    {
3535        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3536        __h.reset(__p.first);
3537    }
3538    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3539                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
3540}
3541
3542template <class _ForwardIterator, class _Predicate>
3543inline _LIBCPP_INLINE_VISIBILITY
3544_ForwardIterator
3545stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3546{
3547    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3548                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3549}
3550
3551// is_sorted_until
3552
3553template <class _ForwardIterator, class _Compare>
3554_ForwardIterator
3555is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3556{
3557    if (__first != __last)
3558    {
3559        _ForwardIterator __i = __first;
3560        while (++__i != __last)
3561        {
3562            if (__comp(*__i, *__first))
3563                return __i;
3564            __first = __i;
3565        }
3566    }
3567    return __last;
3568}
3569
3570template<class _ForwardIterator>
3571inline _LIBCPP_INLINE_VISIBILITY
3572_ForwardIterator
3573is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3574{
3575    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3576}
3577
3578// is_sorted
3579
3580template <class _ForwardIterator, class _Compare>
3581inline _LIBCPP_INLINE_VISIBILITY
3582bool
3583is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3584{
3585    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
3586}
3587
3588template<class _ForwardIterator>
3589inline _LIBCPP_INLINE_VISIBILITY
3590bool
3591is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3592{
3593    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3594}
3595
3596// sort
3597
3598// stable, 2-3 compares, 0-2 swaps
3599
3600template <class _Compare, class _ForwardIterator>
3601unsigned
3602__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
3603{
3604    unsigned __r = 0;
3605    if (!__c(*__y, *__x))          // if x <= y
3606    {
3607        if (!__c(*__z, *__y))      // if y <= z
3608            return __r;            // x <= y && y <= z
3609                                   // x <= y && y > z
3610        swap(*__y, *__z);          // x <= z && y < z
3611        __r = 1;
3612        if (__c(*__y, *__x))       // if x > y
3613        {
3614            swap(*__x, *__y);      // x < y && y <= z
3615            __r = 2;
3616        }
3617        return __r;                // x <= y && y < z
3618    }
3619    if (__c(*__z, *__y))           // x > y, if y > z
3620    {
3621        swap(*__x, *__z);          // x < y && y < z
3622        __r = 1;
3623        return __r;
3624    }
3625    swap(*__x, *__y);              // x > y && y <= z
3626    __r = 1;                       // x < y && x <= z
3627    if (__c(*__z, *__y))           // if y > z
3628    {
3629        swap(*__y, *__z);          // x <= y && y < z
3630        __r = 2;
3631    }
3632    return __r;
3633}                                  // x <= y && y <= z
3634
3635// stable, 3-6 compares, 0-5 swaps
3636
3637template <class _Compare, class _ForwardIterator>
3638unsigned
3639__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3640            _ForwardIterator __x4, _Compare __c)
3641{
3642    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
3643    if (__c(*__x4, *__x3))
3644    {
3645        swap(*__x3, *__x4);
3646        ++__r;
3647        if (__c(*__x3, *__x2))
3648        {
3649            swap(*__x2, *__x3);
3650            ++__r;
3651            if (__c(*__x2, *__x1))
3652            {
3653                swap(*__x1, *__x2);
3654                ++__r;
3655            }
3656        }
3657    }
3658    return __r;
3659}
3660
3661// stable, 4-10 compares, 0-9 swaps
3662
3663template <class _Compare, class _ForwardIterator>
3664unsigned
3665__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3666            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
3667{
3668    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
3669    if (__c(*__x5, *__x4))
3670    {
3671        swap(*__x4, *__x5);
3672        ++__r;
3673        if (__c(*__x4, *__x3))
3674        {
3675            swap(*__x3, *__x4);
3676            ++__r;
3677            if (__c(*__x3, *__x2))
3678            {
3679                swap(*__x2, *__x3);
3680                ++__r;
3681                if (__c(*__x2, *__x1))
3682                {
3683                    swap(*__x1, *__x2);
3684                    ++__r;
3685                }
3686            }
3687        }
3688    }
3689    return __r;
3690}
3691
3692// Assumes size > 0
3693template <class _Compare, class _BirdirectionalIterator>
3694void
3695__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3696{
3697    _BirdirectionalIterator __lm1 = __last;
3698    for (--__lm1; __first != __lm1; ++__first)
3699    {
3700        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
3701                                                        typename add_lvalue_reference<_Compare>::type>
3702                                                       (__first, __last, __comp);
3703        if (__i != __first)
3704            swap(*__first, *__i);
3705    }
3706}
3707
3708template <class _Compare, class _BirdirectionalIterator>
3709void
3710__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3711{
3712    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3713    if (__first != __last)
3714    {
3715        _BirdirectionalIterator __i = __first;
3716        for (++__i; __i != __last; ++__i)
3717        {
3718            _BirdirectionalIterator __j = __i;
3719            value_type __t(_VSTD::move(*__j));
3720            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
3721                *__j = _VSTD::move(*__k);
3722            *__j = _VSTD::move(__t);
3723        }
3724    }
3725}
3726
3727template <class _Compare, class _RandomAccessIterator>
3728void
3729__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3730{
3731    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3732    _RandomAccessIterator __j = __first+2;
3733    __sort3<_Compare>(__first, __first+1, __j, __comp);
3734    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3735    {
3736        if (__comp(*__i, *__j))
3737        {
3738            value_type __t(_VSTD::move(*__i));
3739            _RandomAccessIterator __k = __j;
3740            __j = __i;
3741            do
3742            {
3743                *__j = _VSTD::move(*__k);
3744                __j = __k;
3745            } while (__j != __first && __comp(__t, *--__k));
3746            *__j = _VSTD::move(__t);
3747        }
3748        __j = __i;
3749    }
3750}
3751
3752template <class _Compare, class _RandomAccessIterator>
3753bool
3754__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3755{
3756    switch (__last - __first)
3757    {
3758    case 0:
3759    case 1:
3760        return true;
3761    case 2:
3762        if (__comp(*--__last, *__first))
3763            swap(*__first, *__last);
3764        return true;
3765    case 3:
3766        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3767        return true;
3768    case 4:
3769        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3770        return true;
3771    case 5:
3772        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3773        return true;
3774    }
3775    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3776    _RandomAccessIterator __j = __first+2;
3777    __sort3<_Compare>(__first, __first+1, __j, __comp);
3778    const unsigned __limit = 8;
3779    unsigned __count = 0;
3780    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3781    {
3782        if (__comp(*__i, *__j))
3783        {
3784            value_type __t(_VSTD::move(*__i));
3785            _RandomAccessIterator __k = __j;
3786            __j = __i;
3787            do
3788            {
3789                *__j = _VSTD::move(*__k);
3790                __j = __k;
3791            } while (__j != __first && __comp(__t, *--__k));
3792            *__j = _VSTD::move(__t);
3793            if (++__count == __limit)
3794                return ++__i == __last;
3795        }
3796        __j = __i;
3797    }
3798    return true;
3799}
3800
3801template <class _Compare, class _BirdirectionalIterator>
3802void
3803__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
3804                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
3805{
3806    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3807    if (__first1 != __last1)
3808    {
3809        __destruct_n __d(0);
3810        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
3811        value_type* __last2 = __first2;
3812        ::new(__last2) value_type(_VSTD::move(*__first1));
3813        __d.__incr((value_type*)0);
3814        for (++__last2; ++__first1 != __last1; ++__last2)
3815        {
3816            value_type* __j2 = __last2;
3817            value_type* __i2 = __j2;
3818            if (__comp(*__first1, *--__i2))
3819            {
3820                ::new(__j2) value_type(_VSTD::move(*__i2));
3821                __d.__incr((value_type*)0);
3822                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
3823                    *__j2 = _VSTD::move(*__i2);
3824                *__j2 = _VSTD::move(*__first1);
3825            }
3826            else
3827            {
3828                ::new(__j2) value_type(_VSTD::move(*__first1));
3829                __d.__incr((value_type*)0);
3830            }
3831        }
3832        __h.release();
3833    }
3834}
3835
3836template <class _Compare, class _RandomAccessIterator>
3837void
3838__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3839{
3840    // _Compare is known to be a reference type
3841    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3842    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3843    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
3844                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
3845    while (true)
3846    {
3847    __restart:
3848        difference_type __len = __last - __first;
3849        switch (__len)
3850        {
3851        case 0:
3852        case 1:
3853            return;
3854        case 2:
3855            if (__comp(*--__last, *__first))
3856                swap(*__first, *__last);
3857            return;
3858        case 3:
3859            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3860            return;
3861        case 4:
3862            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3863            return;
3864        case 5:
3865            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3866            return;
3867        }
3868        if (__len <= __limit)
3869        {
3870            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
3871            return;
3872        }
3873        // __len > 5
3874        _RandomAccessIterator __m = __first;
3875        _RandomAccessIterator __lm1 = __last;
3876        --__lm1;
3877        unsigned __n_swaps;
3878        {
3879        difference_type __delta;
3880        if (__len >= 1000)
3881        {
3882            __delta = __len/2;
3883            __m += __delta;
3884            __delta /= 2;
3885            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
3886        }
3887        else
3888        {
3889            __delta = __len/2;
3890            __m += __delta;
3891            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
3892        }
3893        }
3894        // *__m is median
3895        // partition [__first, __m) < *__m and *__m <= [__m, __last)
3896        // (this inhibits tossing elements equivalent to __m around unnecessarily)
3897        _RandomAccessIterator __i = __first;
3898        _RandomAccessIterator __j = __lm1;
3899        // j points beyond range to be tested, *__m is known to be <= *__lm1
3900        // The search going up is known to be guarded but the search coming down isn't.
3901        // Prime the downward search with a guard.
3902        if (!__comp(*__i, *__m))  // if *__first == *__m
3903        {
3904            // *__first == *__m, *__first doesn't go in first part
3905            // manually guard downward moving __j against __i
3906            while (true)
3907            {
3908                if (__i == --__j)
3909                {
3910                    // *__first == *__m, *__m <= all other elements
3911                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
3912                    ++__i;  // __first + 1
3913                    __j = __last;
3914                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
3915                    {
3916                        while (true)
3917                        {
3918                            if (__i == __j)
3919                                return;  // [__first, __last) all equivalent elements
3920                            if (__comp(*__first, *__i))
3921                            {
3922                                swap(*__i, *__j);
3923                                ++__n_swaps;
3924                                ++__i;
3925                                break;
3926                            }
3927                            ++__i;
3928                        }
3929                    }
3930                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
3931                    if (__i == __j)
3932                        return;
3933                    while (true)
3934                    {
3935                        while (!__comp(*__first, *__i))
3936                            ++__i;
3937                        while (__comp(*__first, *--__j))
3938                            ;
3939                        if (__i >= __j)
3940                            break;
3941                        swap(*__i, *__j);
3942                        ++__n_swaps;
3943                        ++__i;
3944                    }
3945                    // [__first, __i) == *__first and *__first < [__i, __last)
3946                    // The first part is sorted, sort the secod part
3947                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
3948                    __first = __i;
3949                    goto __restart;
3950                }
3951                if (__comp(*__j, *__m))
3952                {
3953                    swap(*__i, *__j);
3954                    ++__n_swaps;
3955                    break;  // found guard for downward moving __j, now use unguarded partition
3956                }
3957            }
3958        }
3959        // It is known that *__i < *__m
3960        ++__i;
3961        // j points beyond range to be tested, *__m is known to be <= *__lm1
3962        // if not yet partitioned...
3963        if (__i < __j)
3964        {
3965            // known that *(__i - 1) < *__m
3966            // known that __i <= __m
3967            while (true)
3968            {
3969                // __m still guards upward moving __i
3970                while (__comp(*__i, *__m))
3971                    ++__i;
3972                // It is now known that a guard exists for downward moving __j
3973                while (!__comp(*--__j, *__m))
3974                    ;
3975                if (__i > __j)
3976                    break;
3977                swap(*__i, *__j);
3978                ++__n_swaps;
3979                // It is known that __m != __j
3980                // If __m just moved, follow it
3981                if (__m == __i)
3982                    __m = __j;
3983                ++__i;
3984            }
3985        }
3986        // [__first, __i) < *__m and *__m <= [__i, __last)
3987        if (__i != __m && __comp(*__m, *__i))
3988        {
3989            swap(*__i, *__m);
3990            ++__n_swaps;
3991        }
3992        // [__first, __i) < *__i and *__i <= [__i+1, __last)
3993        // If we were given a perfect partition, see if insertion sort is quick...
3994        if (__n_swaps == 0)
3995        {
3996            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
3997            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
3998            {
3999                if (__fs)
4000                    return;
4001                __last = __i;
4002                continue;
4003            }
4004            else
4005            {
4006                if (__fs)
4007                {
4008                    __first = ++__i;
4009                    continue;
4010                }
4011            }
4012        }
4013        // sort smaller range with recursive call and larger with tail recursion elimination
4014        if (__i - __first < __last - __i)
4015        {
4016            _VSTD::__sort<_Compare>(__first, __i, __comp);
4017            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4018            __first = ++__i;
4019        }
4020        else
4021        {
4022            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4023            // _VSTD::__sort<_Compare>(__first, __i, __comp);
4024            __last = __i;
4025        }
4026    }
4027}
4028
4029// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
4030template <class _RandomAccessIterator, class _Compare>
4031inline _LIBCPP_INLINE_VISIBILITY
4032void
4033sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4034{
4035#ifdef _LIBCPP_DEBUG
4036    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4037    __debug_less<_Compare> __c(__comp);
4038    __sort<_Comp_ref>(__first, __last, __c);
4039#else  // _LIBCPP_DEBUG
4040    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4041    __sort<_Comp_ref>(__first, __last, __comp);
4042#endif  // _LIBCPP_DEBUG
4043}
4044
4045template <class _RandomAccessIterator>
4046inline _LIBCPP_INLINE_VISIBILITY
4047void
4048sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4049{
4050    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4051}
4052
4053template <class _Tp>
4054inline _LIBCPP_INLINE_VISIBILITY
4055void
4056sort(_Tp** __first, _Tp** __last)
4057{
4058    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
4059}
4060
4061template <class _Tp>
4062inline _LIBCPP_INLINE_VISIBILITY
4063void
4064sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
4065{
4066    _VSTD::sort(__first.base(), __last.base());
4067}
4068
4069template <class _Tp, class _Compare>
4070inline _LIBCPP_INLINE_VISIBILITY
4071void
4072sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
4073{
4074    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4075    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
4076}
4077
4078#ifdef _LIBCPP_MSVC
4079#pragma warning( push )
4080#pragma warning( disable: 4231)
4081#endif // _LIBCPP_MSVC
4082_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
4083_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4084_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4085_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4086_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
4087_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4088_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
4089_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4090_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
4091_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4092_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4093_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4094_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
4095_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
4096_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4097
4098_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
4099_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4100_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4101_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4102_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
4103_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4104_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
4105_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4106_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
4107_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4108_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4109_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4110_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
4111_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
4112_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4113
4114_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&))
4115#ifdef _LIBCPP_MSVC
4116#pragma warning( pop )
4117#endif  // _LIBCPP_MSVC
4118
4119// lower_bound
4120
4121template <class _Compare, class _ForwardIterator, class _Tp>
4122_ForwardIterator
4123__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4124{
4125    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4126    difference_type __len = _VSTD::distance(__first, __last);
4127    while (__len != 0)
4128    {
4129        difference_type __l2 = __len / 2;
4130        _ForwardIterator __m = __first;
4131        _VSTD::advance(__m, __l2);
4132        if (__comp(*__m, __value_))
4133        {
4134            __first = ++__m;
4135            __len -= __l2 + 1;
4136        }
4137        else
4138            __len = __l2;
4139    }
4140    return __first;
4141}
4142
4143template <class _ForwardIterator, class _Tp, class _Compare>
4144inline _LIBCPP_INLINE_VISIBILITY
4145_ForwardIterator
4146lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4147{
4148#ifdef _LIBCPP_DEBUG
4149    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4150    __debug_less<_Compare> __c(__comp);
4151    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
4152#else  // _LIBCPP_DEBUG
4153    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4154    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
4155#endif  // _LIBCPP_DEBUG
4156}
4157
4158template <class _ForwardIterator, class _Tp>
4159inline _LIBCPP_INLINE_VISIBILITY
4160_ForwardIterator
4161lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4162{
4163    return _VSTD::lower_bound(__first, __last, __value_,
4164                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4165}
4166
4167// upper_bound
4168
4169template <class _Compare, class _ForwardIterator, class _Tp>
4170_ForwardIterator
4171__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4172{
4173    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4174    difference_type __len = _VSTD::distance(__first, __last);
4175    while (__len != 0)
4176    {
4177        difference_type __l2 = __len / 2;
4178        _ForwardIterator __m = __first;
4179        _VSTD::advance(__m, __l2);
4180        if (__comp(__value_, *__m))
4181            __len = __l2;
4182        else
4183        {
4184            __first = ++__m;
4185            __len -= __l2 + 1;
4186        }
4187    }
4188    return __first;
4189}
4190
4191template <class _ForwardIterator, class _Tp, class _Compare>
4192inline _LIBCPP_INLINE_VISIBILITY
4193_ForwardIterator
4194upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4195{
4196#ifdef _LIBCPP_DEBUG
4197    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4198    __debug_less<_Compare> __c(__comp);
4199    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
4200#else  // _LIBCPP_DEBUG
4201    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4202    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
4203#endif  // _LIBCPP_DEBUG
4204}
4205
4206template <class _ForwardIterator, class _Tp>
4207inline _LIBCPP_INLINE_VISIBILITY
4208_ForwardIterator
4209upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4210{
4211    return _VSTD::upper_bound(__first, __last, __value_,
4212                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
4213}
4214
4215// equal_range
4216
4217template <class _Compare, class _ForwardIterator, class _Tp>
4218pair<_ForwardIterator, _ForwardIterator>
4219__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4220{
4221    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4222    difference_type __len = _VSTD::distance(__first, __last);
4223    while (__len != 0)
4224    {
4225        difference_type __l2 = __len / 2;
4226        _ForwardIterator __m = __first;
4227        _VSTD::advance(__m, __l2);
4228        if (__comp(*__m, __value_))
4229        {
4230            __first = ++__m;
4231            __len -= __l2 + 1;
4232        }
4233        else if (__comp(__value_, *__m))
4234        {
4235            __last = __m;
4236            __len = __l2;
4237        }
4238        else
4239        {
4240            _ForwardIterator __mp1 = __m;
4241            return pair<_ForwardIterator, _ForwardIterator>
4242                   (
4243                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
4244                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
4245                   );
4246        }
4247    }
4248    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
4249}
4250
4251template <class _ForwardIterator, class _Tp, class _Compare>
4252inline _LIBCPP_INLINE_VISIBILITY
4253pair<_ForwardIterator, _ForwardIterator>
4254equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4255{
4256#ifdef _LIBCPP_DEBUG
4257    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4258    __debug_less<_Compare> __c(__comp);
4259    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
4260#else  // _LIBCPP_DEBUG
4261    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4262    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
4263#endif  // _LIBCPP_DEBUG
4264}
4265
4266template <class _ForwardIterator, class _Tp>
4267inline _LIBCPP_INLINE_VISIBILITY
4268pair<_ForwardIterator, _ForwardIterator>
4269equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4270{
4271    return _VSTD::equal_range(__first, __last, __value_,
4272                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4273}
4274
4275// binary_search
4276
4277template <class _Compare, class _ForwardIterator, class _Tp>
4278inline _LIBCPP_INLINE_VISIBILITY
4279bool
4280__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4281{
4282    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
4283    return __first != __last && !__comp(__value_, *__first);
4284}
4285
4286template <class _ForwardIterator, class _Tp, class _Compare>
4287inline _LIBCPP_INLINE_VISIBILITY
4288bool
4289binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4290{
4291#ifdef _LIBCPP_DEBUG
4292    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4293    __debug_less<_Compare> __c(__comp);
4294    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
4295#else  // _LIBCPP_DEBUG
4296    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4297    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
4298#endif  // _LIBCPP_DEBUG
4299}
4300
4301template <class _ForwardIterator, class _Tp>
4302inline _LIBCPP_INLINE_VISIBILITY
4303bool
4304binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4305{
4306    return _VSTD::binary_search(__first, __last, __value_,
4307                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4308}
4309
4310// merge
4311
4312template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4313_OutputIterator
4314__merge(_InputIterator1 __first1, _InputIterator1 __last1,
4315        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4316{
4317    for (; __first1 != __last1; ++__result)
4318    {
4319        if (__first2 == __last2)
4320            return _VSTD::copy(__first1, __last1, __result);
4321        if (__comp(*__first2, *__first1))
4322        {
4323            *__result = *__first2;
4324            ++__first2;
4325        }
4326        else
4327        {
4328            *__result = *__first1;
4329            ++__first1;
4330        }
4331    }
4332    return _VSTD::copy(__first2, __last2, __result);
4333}
4334
4335template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
4336inline _LIBCPP_INLINE_VISIBILITY
4337_OutputIterator
4338merge(_InputIterator1 __first1, _InputIterator1 __last1,
4339      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4340{
4341#ifdef _LIBCPP_DEBUG
4342    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4343    __debug_less<_Compare> __c(__comp);
4344    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
4345#else  // _LIBCPP_DEBUG
4346    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4347    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
4348#endif  // _LIBCPP_DEBUG
4349}
4350
4351template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
4352inline _LIBCPP_INLINE_VISIBILITY
4353_OutputIterator
4354merge(_InputIterator1 __first1, _InputIterator1 __last1,
4355      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
4356{
4357    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
4358    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
4359    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
4360}
4361
4362// inplace_merge
4363
4364template <class _Compare, class _InputIterator1, class _InputIterator2,
4365          class _OutputIterator>
4366void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
4367                          _InputIterator2 __first2, _InputIterator2 __last2,
4368                          _OutputIterator __result, _Compare __comp)
4369{
4370    for (; __first1 != __last1; ++__result)
4371    {
4372        if (__first2 == __last2)
4373        {
4374            _VSTD::move(__first1, __last1, __result);
4375            return;
4376        }
4377
4378        if (__comp(*__first2, *__first1))
4379        {
4380            *__result = _VSTD::move(*__first2);
4381            ++__first2;
4382        }
4383        else
4384        {
4385            *__result = _VSTD::move(*__first1);
4386            ++__first1;
4387        }
4388    }
4389    // __first2 through __last2 are already in the right spot.
4390}
4391
4392template <class _Compare, class _BidirectionalIterator>
4393void
4394__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4395                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4396                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4397                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
4398{
4399    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4400    __destruct_n __d(0);
4401    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4402    if (__len1 <= __len2)
4403    {
4404        value_type* __p = __buff;
4405        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4406            ::new(__p) value_type(_VSTD::move(*__i));
4407        __half_inplace_merge(__buff, __p, __middle, __last, __first, __comp);
4408    }
4409    else
4410    {
4411        value_type* __p = __buff;
4412        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4413            ::new(__p) value_type(_VSTD::move(*__i));
4414        typedef reverse_iterator<_BidirectionalIterator> _RBi;
4415        typedef reverse_iterator<value_type*> _Rv;
4416        __half_inplace_merge(_Rv(__p), _Rv(__buff),
4417                             _RBi(__middle), _RBi(__first),
4418                             _RBi(__last), __negate<_Compare>(__comp));
4419    }
4420}
4421
4422template <class _Compare, class _BidirectionalIterator>
4423void
4424__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4425                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4426                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4427                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
4428{
4429    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4430    while (true)
4431    {
4432        // if __middle == __last, we're done
4433        if (__len2 == 0)
4434            return;
4435        if (__len1 <= __buff_size || __len2 <= __buff_size)
4436            return __buffered_inplace_merge<_Compare>
4437                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
4438        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
4439        for (; true; ++__first, (void) --__len1)
4440        {
4441            if (__len1 == 0)
4442                return;
4443            if (__comp(*__middle, *__first))
4444                break;
4445        }
4446        // __first < __middle < __last
4447        // *__first > *__middle
4448        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
4449        //     all elements in:
4450        //         [__first, __m1)  <= [__middle, __m2)
4451        //         [__middle, __m2) <  [__m1, __middle)
4452        //         [__m1, __middle) <= [__m2, __last)
4453        //     and __m1 or __m2 is in the middle of its range
4454        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
4455        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
4456        difference_type __len11;      // distance(__first, __m1)
4457        difference_type __len21;      // distance(__middle, __m2)
4458        // binary search smaller range
4459        if (__len1 < __len2)
4460        {   // __len >= 1, __len2 >= 2
4461            __len21 = __len2 / 2;
4462            __m2 = __middle;
4463            _VSTD::advance(__m2, __len21);
4464            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
4465            __len11 = _VSTD::distance(__first, __m1);
4466        }
4467        else
4468        {
4469            if (__len1 == 1)
4470            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
4471                // It is known *__first > *__middle
4472                swap(*__first, *__middle);
4473                return;
4474            }
4475            // __len1 >= 2, __len2 >= 1
4476            __len11 = __len1 / 2;
4477            __m1 = __first;
4478            _VSTD::advance(__m1, __len11);
4479            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
4480            __len21 = _VSTD::distance(__middle, __m2);
4481        }
4482        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
4483        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
4484        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
4485        // swap middle two partitions
4486        __middle = _VSTD::rotate(__m1, __middle, __m2);
4487        // __len12 and __len21 now have swapped meanings
4488        // merge smaller range with recurisve call and larger with tail recursion elimination
4489        if (__len11 + __len21 < __len12 + __len22)
4490        {
4491            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4492//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4493            __first = __middle;
4494            __middle = __m2;
4495            __len1 = __len12;
4496            __len2 = __len22;
4497        }
4498        else
4499        {
4500            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4501//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4502            __last = __middle;
4503            __middle = __m1;
4504            __len1 = __len11;
4505            __len2 = __len21;
4506        }
4507    }
4508}
4509
4510template <class _BidirectionalIterator, class _Compare>
4511inline _LIBCPP_INLINE_VISIBILITY
4512void
4513inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4514              _Compare __comp)
4515{
4516    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4517    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4518    difference_type __len1 = _VSTD::distance(__first, __middle);
4519    difference_type __len2 = _VSTD::distance(__middle, __last);
4520    difference_type __buf_size = _VSTD::min(__len1, __len2);
4521    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
4522    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
4523
4524#ifdef _LIBCPP_DEBUG
4525    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4526    __debug_less<_Compare> __c(__comp);
4527    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
4528                                            __buf.first, __buf.second);
4529#else  // _LIBCPP_DEBUG
4530    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4531    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
4532                                            __buf.first, __buf.second);
4533#endif  // _LIBCPP_DEBUG
4534}
4535
4536template <class _BidirectionalIterator>
4537inline _LIBCPP_INLINE_VISIBILITY
4538void
4539inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
4540{
4541    _VSTD::inplace_merge(__first, __middle, __last,
4542                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
4543}
4544
4545// stable_sort
4546
4547template <class _Compare, class _InputIterator1, class _InputIterator2>
4548void
4549__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
4550        _InputIterator2 __first2, _InputIterator2 __last2,
4551        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
4552{
4553    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
4554    __destruct_n __d(0);
4555    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
4556    for (; true; ++__result)
4557    {
4558        if (__first1 == __last1)
4559        {
4560            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
4561                ::new (__result) value_type(_VSTD::move(*__first2));
4562            __h.release();
4563            return;
4564        }
4565        if (__first2 == __last2)
4566        {
4567            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
4568                ::new (__result) value_type(_VSTD::move(*__first1));
4569            __h.release();
4570            return;
4571        }
4572        if (__comp(*__first2, *__first1))
4573        {
4574            ::new (__result) value_type(_VSTD::move(*__first2));
4575            __d.__incr((value_type*)0);
4576            ++__first2;
4577        }
4578        else
4579        {
4580            ::new (__result) value_type(_VSTD::move(*__first1));
4581            __d.__incr((value_type*)0);
4582            ++__first1;
4583        }
4584    }
4585}
4586
4587template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4588void
4589__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
4590        _InputIterator2 __first2, _InputIterator2 __last2,
4591        _OutputIterator __result, _Compare __comp)
4592{
4593    for (; __first1 != __last1; ++__result)
4594    {
4595        if (__first2 == __last2)
4596        {
4597            for (; __first1 != __last1; ++__first1, ++__result)
4598                *__result = _VSTD::move(*__first1);
4599            return;
4600        }
4601        if (__comp(*__first2, *__first1))
4602        {
4603            *__result = _VSTD::move(*__first2);
4604            ++__first2;
4605        }
4606        else
4607        {
4608            *__result = _VSTD::move(*__first1);
4609            ++__first1;
4610        }
4611    }
4612    for (; __first2 != __last2; ++__first2, ++__result)
4613        *__result = _VSTD::move(*__first2);
4614}
4615
4616template <class _Compare, class _RandomAccessIterator>
4617void
4618__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4619              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4620              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
4621
4622template <class _Compare, class _RandomAccessIterator>
4623void
4624__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
4625                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4626                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
4627{
4628    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4629    switch (__len)
4630    {
4631    case 0:
4632        return;
4633    case 1:
4634        ::new(__first2) value_type(_VSTD::move(*__first1));
4635        return;
4636    case 2:
4637       __destruct_n __d(0);
4638        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
4639         if (__comp(*--__last1, *__first1))
4640        {
4641            ::new(__first2) value_type(_VSTD::move(*__last1));
4642            __d.__incr((value_type*)0);
4643            ++__first2;
4644            ::new(__first2) value_type(_VSTD::move(*__first1));
4645        }
4646        else
4647        {
4648            ::new(__first2) value_type(_VSTD::move(*__first1));
4649            __d.__incr((value_type*)0);
4650            ++__first2;
4651            ::new(__first2) value_type(_VSTD::move(*__last1));
4652        }
4653        __h2.release();
4654        return;
4655    }
4656    if (__len <= 8)
4657    {
4658        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
4659        return;
4660    }
4661    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4662    _RandomAccessIterator __m = __first1 + __l2;
4663    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
4664    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
4665    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
4666}
4667
4668template <class _Tp>
4669struct __stable_sort_switch
4670{
4671    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
4672};
4673
4674template <class _Compare, class _RandomAccessIterator>
4675void
4676__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4677              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4678              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
4679{
4680    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4681    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4682    switch (__len)
4683    {
4684    case 0:
4685    case 1:
4686        return;
4687    case 2:
4688        if (__comp(*--__last, *__first))
4689            swap(*__first, *__last);
4690        return;
4691    }
4692    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4693    {
4694        __insertion_sort<_Compare>(__first, __last, __comp);
4695        return;
4696    }
4697    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4698    _RandomAccessIterator __m = __first + __l2;
4699    if (__len <= __buff_size)
4700    {
4701        __destruct_n __d(0);
4702        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4703        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
4704        __d.__set(__l2, (value_type*)0);
4705        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
4706        __d.__set(__len, (value_type*)0);
4707        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
4708//         __merge<_Compare>(move_iterator<value_type*>(__buff),
4709//                           move_iterator<value_type*>(__buff + __l2),
4710//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
4711//                           move_iterator<_RandomAccessIterator>(__buff + __len),
4712//                           __first, __comp);
4713        return;
4714    }
4715    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
4716    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
4717    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
4718}
4719
4720template <class _RandomAccessIterator, class _Compare>
4721inline _LIBCPP_INLINE_VISIBILITY
4722void
4723stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4724{
4725    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4726    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4727    difference_type __len = __last - __first;
4728    pair<value_type*, ptrdiff_t> __buf(0, 0);
4729    unique_ptr<value_type, __return_temporary_buffer> __h;
4730    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4731    {
4732        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
4733        __h.reset(__buf.first);
4734    }
4735#ifdef _LIBCPP_DEBUG
4736    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4737    __debug_less<_Compare> __c(__comp);
4738    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
4739#else  // _LIBCPP_DEBUG
4740    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4741    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
4742#endif  // _LIBCPP_DEBUG
4743}
4744
4745template <class _RandomAccessIterator>
4746inline _LIBCPP_INLINE_VISIBILITY
4747void
4748stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4749{
4750    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4751}
4752
4753// is_heap_until
4754
4755template <class _RandomAccessIterator, class _Compare>
4756_RandomAccessIterator
4757is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4758{
4759    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4760    difference_type __len = __last - __first;
4761    difference_type __p = 0;
4762    difference_type __c = 1;
4763    _RandomAccessIterator __pp = __first;
4764    while (__c < __len)
4765    {
4766        _RandomAccessIterator __cp = __first + __c;
4767        if (__comp(*__pp, *__cp))
4768            return __cp;
4769        ++__c;
4770        ++__cp;
4771        if (__c == __len)
4772            return __last;
4773        if (__comp(*__pp, *__cp))
4774            return __cp;
4775        ++__p;
4776        ++__pp;
4777        __c = 2 * __p + 1;
4778    }
4779    return __last;
4780}
4781
4782template<class _RandomAccessIterator>
4783inline _LIBCPP_INLINE_VISIBILITY
4784_RandomAccessIterator
4785is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
4786{
4787    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4788}
4789
4790// is_heap
4791
4792template <class _RandomAccessIterator, class _Compare>
4793inline _LIBCPP_INLINE_VISIBILITY
4794bool
4795is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4796{
4797    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
4798}
4799
4800template<class _RandomAccessIterator>
4801inline _LIBCPP_INLINE_VISIBILITY
4802bool
4803is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4804{
4805    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4806}
4807
4808// push_heap
4809
4810template <class _Compare, class _RandomAccessIterator>
4811void
4812__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4813          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4814{
4815    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4816    if (__len > 1)
4817    {
4818        __len = (__len - 2) / 2;
4819        _RandomAccessIterator __ptr = __first + __len;
4820        if (__comp(*__ptr, *--__last))
4821        {
4822            value_type __t(_VSTD::move(*__last));
4823            do
4824            {
4825                *__last = _VSTD::move(*__ptr);
4826                __last = __ptr;
4827                if (__len == 0)
4828                    break;
4829                __len = (__len - 1) / 2;
4830                __ptr = __first + __len;
4831            } while (__comp(*__ptr, __t));
4832            *__last = _VSTD::move(__t);
4833        }
4834    }
4835}
4836
4837template <class _RandomAccessIterator, class _Compare>
4838inline _LIBCPP_INLINE_VISIBILITY
4839void
4840push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4841{
4842#ifdef _LIBCPP_DEBUG
4843    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4844    __debug_less<_Compare> __c(__comp);
4845    __sift_up<_Comp_ref>(__first, __last, __c, __last - __first);
4846#else  // _LIBCPP_DEBUG
4847    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4848    __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
4849#endif  // _LIBCPP_DEBUG
4850}
4851
4852template <class _RandomAccessIterator>
4853inline _LIBCPP_INLINE_VISIBILITY
4854void
4855push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4856{
4857    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4858}
4859
4860// pop_heap
4861
4862template <class _Compare, class _RandomAccessIterator>
4863void
4864__sift_down(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4865            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4866            _RandomAccessIterator __start)
4867{
4868    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4869    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4870    // left-child of __start is at 2 * __start + 1
4871    // right-child of __start is at 2 * __start + 2
4872    difference_type __child = __start - __first;
4873
4874    if (__len < 2 || (__len - 2) / 2 < __child)
4875        return;
4876
4877    __child = 2 * __child + 1;
4878    _RandomAccessIterator __child_i = __first + __child;
4879
4880    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4881        // right-child exists and is greater than left-child
4882        ++__child_i;
4883        ++__child;
4884    }
4885
4886    // check if we are in heap-order
4887    if (__comp(*__child_i, *__start))
4888        // we are, __start is larger than it's largest child
4889        return;
4890
4891    value_type __top(_VSTD::move(*__start));
4892    do
4893    {
4894        // we are not in heap-order, swap the parent with it's largest child
4895        *__start = _VSTD::move(*__child_i);
4896        __start = __child_i;
4897
4898        if ((__len - 2) / 2 < __child)
4899            break;
4900
4901        // recompute the child based off of the updated parent
4902        __child = 2 * __child + 1;
4903        __child_i = __first + __child;
4904
4905        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4906            // right-child exists and is greater than left-child
4907            ++__child_i;
4908            ++__child;
4909        }
4910
4911        // check if we are in heap-order
4912    } while (!__comp(*__child_i, __top));
4913    *__start = _VSTD::move(__top);
4914}
4915
4916template <class _Compare, class _RandomAccessIterator>
4917inline _LIBCPP_INLINE_VISIBILITY
4918void
4919__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4920           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4921{
4922    if (__len > 1)
4923    {
4924        swap(*__first, *--__last);
4925        __sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
4926    }
4927}
4928
4929template <class _RandomAccessIterator, class _Compare>
4930inline _LIBCPP_INLINE_VISIBILITY
4931void
4932pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4933{
4934#ifdef _LIBCPP_DEBUG
4935    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4936    __debug_less<_Compare> __c(__comp);
4937    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
4938#else  // _LIBCPP_DEBUG
4939    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4940    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
4941#endif  // _LIBCPP_DEBUG
4942}
4943
4944template <class _RandomAccessIterator>
4945inline _LIBCPP_INLINE_VISIBILITY
4946void
4947pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4948{
4949    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4950}
4951
4952// make_heap
4953
4954template <class _Compare, class _RandomAccessIterator>
4955void
4956__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4957{
4958    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4959    difference_type __n = __last - __first;
4960    if (__n > 1)
4961    {
4962        // start from the first parent, there is no need to consider children
4963        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
4964        {
4965            __sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
4966        }
4967    }
4968}
4969
4970template <class _RandomAccessIterator, class _Compare>
4971inline _LIBCPP_INLINE_VISIBILITY
4972void
4973make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4974{
4975#ifdef _LIBCPP_DEBUG
4976    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4977    __debug_less<_Compare> __c(__comp);
4978    __make_heap<_Comp_ref>(__first, __last, __c);
4979#else  // _LIBCPP_DEBUG
4980    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4981    __make_heap<_Comp_ref>(__first, __last, __comp);
4982#endif  // _LIBCPP_DEBUG
4983}
4984
4985template <class _RandomAccessIterator>
4986inline _LIBCPP_INLINE_VISIBILITY
4987void
4988make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4989{
4990    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4991}
4992
4993// sort_heap
4994
4995template <class _Compare, class _RandomAccessIterator>
4996void
4997__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4998{
4999    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5000    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
5001        __pop_heap<_Compare>(__first, __last, __comp, __n);
5002}
5003
5004template <class _RandomAccessIterator, class _Compare>
5005inline _LIBCPP_INLINE_VISIBILITY
5006void
5007sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5008{
5009#ifdef _LIBCPP_DEBUG
5010    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5011    __debug_less<_Compare> __c(__comp);
5012    __sort_heap<_Comp_ref>(__first, __last, __c);
5013#else  // _LIBCPP_DEBUG
5014    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5015    __sort_heap<_Comp_ref>(__first, __last, __comp);
5016#endif  // _LIBCPP_DEBUG
5017}
5018
5019template <class _RandomAccessIterator>
5020inline _LIBCPP_INLINE_VISIBILITY
5021void
5022sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5023{
5024    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5025}
5026
5027// partial_sort
5028
5029template <class _Compare, class _RandomAccessIterator>
5030void
5031__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5032             _Compare __comp)
5033{
5034    __make_heap<_Compare>(__first, __middle, __comp);
5035    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
5036    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
5037    {
5038        if (__comp(*__i, *__first))
5039        {
5040            swap(*__i, *__first);
5041            __sift_down<_Compare>(__first, __middle, __comp, __len, __first);
5042        }
5043    }
5044    __sort_heap<_Compare>(__first, __middle, __comp);
5045}
5046
5047template <class _RandomAccessIterator, class _Compare>
5048inline _LIBCPP_INLINE_VISIBILITY
5049void
5050partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5051             _Compare __comp)
5052{
5053#ifdef _LIBCPP_DEBUG
5054    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5055    __debug_less<_Compare> __c(__comp);
5056    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
5057#else  // _LIBCPP_DEBUG
5058    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5059    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
5060#endif  // _LIBCPP_DEBUG
5061}
5062
5063template <class _RandomAccessIterator>
5064inline _LIBCPP_INLINE_VISIBILITY
5065void
5066partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
5067{
5068    _VSTD::partial_sort(__first, __middle, __last,
5069                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5070}
5071
5072// partial_sort_copy
5073
5074template <class _Compare, class _InputIterator, class _RandomAccessIterator>
5075_RandomAccessIterator
5076__partial_sort_copy(_InputIterator __first, _InputIterator __last,
5077                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5078{
5079    _RandomAccessIterator __r = __result_first;
5080    if (__r != __result_last)
5081    {
5082        for (; __first != __last && __r != __result_last; (void) ++__first, ++__r)
5083            *__r = *__first;
5084        __make_heap<_Compare>(__result_first, __r, __comp);
5085        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
5086        for (; __first != __last; ++__first)
5087            if (__comp(*__first, *__result_first))
5088            {
5089                *__result_first = *__first;
5090                __sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
5091            }
5092        __sort_heap<_Compare>(__result_first, __r, __comp);
5093    }
5094    return __r;
5095}
5096
5097template <class _InputIterator, class _RandomAccessIterator, class _Compare>
5098inline _LIBCPP_INLINE_VISIBILITY
5099_RandomAccessIterator
5100partial_sort_copy(_InputIterator __first, _InputIterator __last,
5101                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5102{
5103#ifdef _LIBCPP_DEBUG
5104    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5105    __debug_less<_Compare> __c(__comp);
5106    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
5107#else  // _LIBCPP_DEBUG
5108    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5109    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
5110#endif  // _LIBCPP_DEBUG
5111}
5112
5113template <class _InputIterator, class _RandomAccessIterator>
5114inline _LIBCPP_INLINE_VISIBILITY
5115_RandomAccessIterator
5116partial_sort_copy(_InputIterator __first, _InputIterator __last,
5117                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
5118{
5119    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
5120                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5121}
5122
5123// nth_element
5124
5125template <class _Compare, class _RandomAccessIterator>
5126void
5127__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5128{
5129    // _Compare is known to be a reference type
5130    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5131    const difference_type __limit = 7;
5132    while (true)
5133    {
5134    __restart:
5135        if (__nth == __last)
5136            return;
5137        difference_type __len = __last - __first;
5138        switch (__len)
5139        {
5140        case 0:
5141        case 1:
5142            return;
5143        case 2:
5144            if (__comp(*--__last, *__first))
5145                swap(*__first, *__last);
5146            return;
5147        case 3:
5148            {
5149            _RandomAccessIterator __m = __first;
5150            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
5151            return;
5152            }
5153        }
5154        if (__len <= __limit)
5155        {
5156            __selection_sort<_Compare>(__first, __last, __comp);
5157            return;
5158        }
5159        // __len > __limit >= 3
5160        _RandomAccessIterator __m = __first + __len/2;
5161        _RandomAccessIterator __lm1 = __last;
5162        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
5163        // *__m is median
5164        // partition [__first, __m) < *__m and *__m <= [__m, __last)
5165        // (this inhibits tossing elements equivalent to __m around unnecessarily)
5166        _RandomAccessIterator __i = __first;
5167        _RandomAccessIterator __j = __lm1;
5168        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5169        // The search going up is known to be guarded but the search coming down isn't.
5170        // Prime the downward search with a guard.
5171        if (!__comp(*__i, *__m))  // if *__first == *__m
5172        {
5173            // *__first == *__m, *__first doesn't go in first part
5174            // manually guard downward moving __j against __i
5175            while (true)
5176            {
5177                if (__i == --__j)
5178                {
5179                    // *__first == *__m, *__m <= all other elements
5180                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
5181                    ++__i;  // __first + 1
5182                    __j = __last;
5183                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
5184                    {
5185                        while (true)
5186                        {
5187                            if (__i == __j)
5188                                return;  // [__first, __last) all equivalent elements
5189                            if (__comp(*__first, *__i))
5190                            {
5191                                swap(*__i, *__j);
5192                                ++__n_swaps;
5193                                ++__i;
5194                                break;
5195                            }
5196                            ++__i;
5197                        }
5198                    }
5199                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
5200                    if (__i == __j)
5201                        return;
5202                    while (true)
5203                    {
5204                        while (!__comp(*__first, *__i))
5205                            ++__i;
5206                        while (__comp(*__first, *--__j))
5207                            ;
5208                        if (__i >= __j)
5209                            break;
5210                        swap(*__i, *__j);
5211                        ++__n_swaps;
5212                        ++__i;
5213                    }
5214                    // [__first, __i) == *__first and *__first < [__i, __last)
5215                    // The first part is sorted,
5216                    if (__nth < __i)
5217                        return;
5218                    // __nth_element the secod part
5219                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
5220                    __first = __i;
5221                    goto __restart;
5222                }
5223                if (__comp(*__j, *__m))
5224                {
5225                    swap(*__i, *__j);
5226                    ++__n_swaps;
5227                    break;  // found guard for downward moving __j, now use unguarded partition
5228                }
5229            }
5230        }
5231        ++__i;
5232        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5233        // if not yet partitioned...
5234        if (__i < __j)
5235        {
5236            // known that *(__i - 1) < *__m
5237            while (true)
5238            {
5239                // __m still guards upward moving __i
5240                while (__comp(*__i, *__m))
5241                    ++__i;
5242                // It is now known that a guard exists for downward moving __j
5243                while (!__comp(*--__j, *__m))
5244                    ;
5245                if (__i >= __j)
5246                    break;
5247                swap(*__i, *__j);
5248                ++__n_swaps;
5249                // It is known that __m != __j
5250                // If __m just moved, follow it
5251                if (__m == __i)
5252                    __m = __j;
5253                ++__i;
5254            }
5255        }
5256        // [__first, __i) < *__m and *__m <= [__i, __last)
5257        if (__i != __m && __comp(*__m, *__i))
5258        {
5259            swap(*__i, *__m);
5260            ++__n_swaps;
5261        }
5262        // [__first, __i) < *__i and *__i <= [__i+1, __last)
5263        if (__nth == __i)
5264            return;
5265        if (__n_swaps == 0)
5266        {
5267            // We were given a perfectly partitioned sequence.  Coincidence?
5268            if (__nth < __i)
5269            {
5270                // Check for [__first, __i) already sorted
5271                __j = __m = __first;
5272                while (++__j != __i)
5273                {
5274                    if (__comp(*__j, *__m))
5275                        // not yet sorted, so sort
5276                        goto not_sorted;
5277                    __m = __j;
5278                }
5279                // [__first, __i) sorted
5280                return;
5281            }
5282            else
5283            {
5284                // Check for [__i, __last) already sorted
5285                __j = __m = __i;
5286                while (++__j != __last)
5287                {
5288                    if (__comp(*__j, *__m))
5289                        // not yet sorted, so sort
5290                        goto not_sorted;
5291                    __m = __j;
5292                }
5293                // [__i, __last) sorted
5294                return;
5295            }
5296        }
5297not_sorted:
5298        // __nth_element on range containing __nth
5299        if (__nth < __i)
5300        {
5301            // __nth_element<_Compare>(__first, __nth, __i, __comp);
5302            __last = __i;
5303        }
5304        else
5305        {
5306            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
5307            __first = ++__i;
5308        }
5309    }
5310}
5311
5312template <class _RandomAccessIterator, class _Compare>
5313inline _LIBCPP_INLINE_VISIBILITY
5314void
5315nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5316{
5317#ifdef _LIBCPP_DEBUG
5318    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5319    __debug_less<_Compare> __c(__comp);
5320    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
5321#else  // _LIBCPP_DEBUG
5322    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5323    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
5324#endif  // _LIBCPP_DEBUG
5325}
5326
5327template <class _RandomAccessIterator>
5328inline _LIBCPP_INLINE_VISIBILITY
5329void
5330nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
5331{
5332    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5333}
5334
5335// includes
5336
5337template <class _Compare, class _InputIterator1, class _InputIterator2>
5338bool
5339__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5340           _Compare __comp)
5341{
5342    for (; __first2 != __last2; ++__first1)
5343    {
5344        if (__first1 == __last1 || __comp(*__first2, *__first1))
5345            return false;
5346        if (!__comp(*__first1, *__first2))
5347            ++__first2;
5348    }
5349    return true;
5350}
5351
5352template <class _InputIterator1, class _InputIterator2, class _Compare>
5353inline _LIBCPP_INLINE_VISIBILITY
5354bool
5355includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5356         _Compare __comp)
5357{
5358#ifdef _LIBCPP_DEBUG
5359    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5360    __debug_less<_Compare> __c(__comp);
5361    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5362#else  // _LIBCPP_DEBUG
5363    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5364    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5365#endif  // _LIBCPP_DEBUG
5366}
5367
5368template <class _InputIterator1, class _InputIterator2>
5369inline _LIBCPP_INLINE_VISIBILITY
5370bool
5371includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
5372{
5373    return _VSTD::includes(__first1, __last1, __first2, __last2,
5374                          __less<typename iterator_traits<_InputIterator1>::value_type,
5375                                 typename iterator_traits<_InputIterator2>::value_type>());
5376}
5377
5378// set_union
5379
5380template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5381_OutputIterator
5382__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5383            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5384{
5385    for (; __first1 != __last1; ++__result)
5386    {
5387        if (__first2 == __last2)
5388            return _VSTD::copy(__first1, __last1, __result);
5389        if (__comp(*__first2, *__first1))
5390        {
5391            *__result = *__first2;
5392            ++__first2;
5393        }
5394        else
5395        {
5396            *__result = *__first1;
5397            if (!__comp(*__first1, *__first2))
5398                ++__first2;
5399            ++__first1;
5400        }
5401    }
5402    return _VSTD::copy(__first2, __last2, __result);
5403}
5404
5405template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5406inline _LIBCPP_INLINE_VISIBILITY
5407_OutputIterator
5408set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5409          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5410{
5411#ifdef _LIBCPP_DEBUG
5412    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5413    __debug_less<_Compare> __c(__comp);
5414    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5415#else  // _LIBCPP_DEBUG
5416    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5417    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5418#endif  // _LIBCPP_DEBUG
5419}
5420
5421template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5422inline _LIBCPP_INLINE_VISIBILITY
5423_OutputIterator
5424set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5425          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5426{
5427    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
5428                          __less<typename iterator_traits<_InputIterator1>::value_type,
5429                                 typename iterator_traits<_InputIterator2>::value_type>());
5430}
5431
5432// set_intersection
5433
5434template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5435_OutputIterator
5436__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5437                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5438{
5439    while (__first1 != __last1 && __first2 != __last2)
5440    {
5441        if (__comp(*__first1, *__first2))
5442            ++__first1;
5443        else
5444        {
5445            if (!__comp(*__first2, *__first1))
5446            {
5447                *__result = *__first1;
5448                ++__result;
5449                ++__first1;
5450            }
5451            ++__first2;
5452        }
5453    }
5454    return __result;
5455}
5456
5457template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5458inline _LIBCPP_INLINE_VISIBILITY
5459_OutputIterator
5460set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5461                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5462{
5463#ifdef _LIBCPP_DEBUG
5464    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5465    __debug_less<_Compare> __c(__comp);
5466    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5467#else  // _LIBCPP_DEBUG
5468    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5469    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5470#endif  // _LIBCPP_DEBUG
5471}
5472
5473template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5474inline _LIBCPP_INLINE_VISIBILITY
5475_OutputIterator
5476set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5477                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5478{
5479    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
5480                                  __less<typename iterator_traits<_InputIterator1>::value_type,
5481                                         typename iterator_traits<_InputIterator2>::value_type>());
5482}
5483
5484// set_difference
5485
5486template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5487_OutputIterator
5488__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5489                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5490{
5491    while (__first1 != __last1)
5492    {
5493        if (__first2 == __last2)
5494            return _VSTD::copy(__first1, __last1, __result);
5495        if (__comp(*__first1, *__first2))
5496        {
5497            *__result = *__first1;
5498            ++__result;
5499            ++__first1;
5500        }
5501        else
5502        {
5503            if (!__comp(*__first2, *__first1))
5504                ++__first1;
5505            ++__first2;
5506        }
5507    }
5508    return __result;
5509}
5510
5511template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5512inline _LIBCPP_INLINE_VISIBILITY
5513_OutputIterator
5514set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5515               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5516{
5517#ifdef _LIBCPP_DEBUG
5518    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5519    __debug_less<_Compare> __c(__comp);
5520    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5521#else  // _LIBCPP_DEBUG
5522    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5523    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5524#endif  // _LIBCPP_DEBUG
5525}
5526
5527template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5528inline _LIBCPP_INLINE_VISIBILITY
5529_OutputIterator
5530set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5531               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5532{
5533    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
5534                                __less<typename iterator_traits<_InputIterator1>::value_type,
5535                                       typename iterator_traits<_InputIterator2>::value_type>());
5536}
5537
5538// set_symmetric_difference
5539
5540template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5541_OutputIterator
5542__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5543                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5544{
5545    while (__first1 != __last1)
5546    {
5547        if (__first2 == __last2)
5548            return _VSTD::copy(__first1, __last1, __result);
5549        if (__comp(*__first1, *__first2))
5550        {
5551            *__result = *__first1;
5552            ++__result;
5553            ++__first1;
5554        }
5555        else
5556        {
5557            if (__comp(*__first2, *__first1))
5558            {
5559                *__result = *__first2;
5560                ++__result;
5561            }
5562            else
5563                ++__first1;
5564            ++__first2;
5565        }
5566    }
5567    return _VSTD::copy(__first2, __last2, __result);
5568}
5569
5570template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5571inline _LIBCPP_INLINE_VISIBILITY
5572_OutputIterator
5573set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5574                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5575{
5576#ifdef _LIBCPP_DEBUG
5577    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5578    __debug_less<_Compare> __c(__comp);
5579    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5580#else  // _LIBCPP_DEBUG
5581    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5582    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5583#endif  // _LIBCPP_DEBUG
5584}
5585
5586template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5587inline _LIBCPP_INLINE_VISIBILITY
5588_OutputIterator
5589set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5590                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5591{
5592    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
5593                                          __less<typename iterator_traits<_InputIterator1>::value_type,
5594                                                 typename iterator_traits<_InputIterator2>::value_type>());
5595}
5596
5597// lexicographical_compare
5598
5599template <class _Compare, class _InputIterator1, class _InputIterator2>
5600bool
5601__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5602                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5603{
5604    for (; __first2 != __last2; ++__first1, (void) ++__first2)
5605    {
5606        if (__first1 == __last1 || __comp(*__first1, *__first2))
5607            return true;
5608        if (__comp(*__first2, *__first1))
5609            return false;
5610    }
5611    return false;
5612}
5613
5614template <class _InputIterator1, class _InputIterator2, class _Compare>
5615inline _LIBCPP_INLINE_VISIBILITY
5616bool
5617lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5618                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5619{
5620#ifdef _LIBCPP_DEBUG
5621    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5622    __debug_less<_Compare> __c(__comp);
5623    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5624#else  // _LIBCPP_DEBUG
5625    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5626    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5627#endif  // _LIBCPP_DEBUG
5628}
5629
5630template <class _InputIterator1, class _InputIterator2>
5631inline _LIBCPP_INLINE_VISIBILITY
5632bool
5633lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5634                        _InputIterator2 __first2, _InputIterator2 __last2)
5635{
5636    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
5637                                         __less<typename iterator_traits<_InputIterator1>::value_type,
5638                                                typename iterator_traits<_InputIterator2>::value_type>());
5639}
5640
5641// next_permutation
5642
5643template <class _Compare, class _BidirectionalIterator>
5644bool
5645__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5646{
5647    _BidirectionalIterator __i = __last;
5648    if (__first == __last || __first == --__i)
5649        return false;
5650    while (true)
5651    {
5652        _BidirectionalIterator __ip1 = __i;
5653        if (__comp(*--__i, *__ip1))
5654        {
5655            _BidirectionalIterator __j = __last;
5656            while (!__comp(*__i, *--__j))
5657                ;
5658            swap(*__i, *__j);
5659            _VSTD::reverse(__ip1, __last);
5660            return true;
5661        }
5662        if (__i == __first)
5663        {
5664            _VSTD::reverse(__first, __last);
5665            return false;
5666        }
5667    }
5668}
5669
5670template <class _BidirectionalIterator, class _Compare>
5671inline _LIBCPP_INLINE_VISIBILITY
5672bool
5673next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5674{
5675#ifdef _LIBCPP_DEBUG
5676    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5677    __debug_less<_Compare> __c(__comp);
5678    return __next_permutation<_Comp_ref>(__first, __last, __c);
5679#else  // _LIBCPP_DEBUG
5680    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5681    return __next_permutation<_Comp_ref>(__first, __last, __comp);
5682#endif  // _LIBCPP_DEBUG
5683}
5684
5685template <class _BidirectionalIterator>
5686inline _LIBCPP_INLINE_VISIBILITY
5687bool
5688next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5689{
5690    return _VSTD::next_permutation(__first, __last,
5691                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5692}
5693
5694// prev_permutation
5695
5696template <class _Compare, class _BidirectionalIterator>
5697bool
5698__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5699{
5700    _BidirectionalIterator __i = __last;
5701    if (__first == __last || __first == --__i)
5702        return false;
5703    while (true)
5704    {
5705        _BidirectionalIterator __ip1 = __i;
5706        if (__comp(*__ip1, *--__i))
5707        {
5708            _BidirectionalIterator __j = __last;
5709            while (!__comp(*--__j, *__i))
5710                ;
5711            swap(*__i, *__j);
5712            _VSTD::reverse(__ip1, __last);
5713            return true;
5714        }
5715        if (__i == __first)
5716        {
5717            _VSTD::reverse(__first, __last);
5718            return false;
5719        }
5720    }
5721}
5722
5723template <class _BidirectionalIterator, class _Compare>
5724inline _LIBCPP_INLINE_VISIBILITY
5725bool
5726prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5727{
5728#ifdef _LIBCPP_DEBUG
5729    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5730    __debug_less<_Compare> __c(__comp);
5731    return __prev_permutation<_Comp_ref>(__first, __last, __c);
5732#else  // _LIBCPP_DEBUG
5733    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5734    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
5735#endif  // _LIBCPP_DEBUG
5736}
5737
5738template <class _BidirectionalIterator>
5739inline _LIBCPP_INLINE_VISIBILITY
5740bool
5741prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5742{
5743    return _VSTD::prev_permutation(__first, __last,
5744                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5745}
5746
5747template <class _Tp>
5748inline _LIBCPP_INLINE_VISIBILITY
5749typename enable_if
5750<
5751    is_integral<_Tp>::value,
5752    _Tp
5753>::type
5754__rotate_left(_Tp __t, _Tp __n = 1)
5755{
5756    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5757    __n &= __bits;
5758    return static_cast<_Tp>((__t << __n) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> (__bits - __n)));
5759}
5760
5761template <class _Tp>
5762inline _LIBCPP_INLINE_VISIBILITY
5763typename enable_if
5764<
5765    is_integral<_Tp>::value,
5766    _Tp
5767>::type
5768__rotate_right(_Tp __t, _Tp __n = 1)
5769{
5770    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5771    __n &= __bits;
5772    return static_cast<_Tp>((__t << (__bits - __n)) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> __n));
5773}
5774
5775_LIBCPP_END_NAMESPACE_STD
5776
5777#endif  // _LIBCPP_ALGORITHM
5778