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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_UNORDERED_SET
11#define _LIBCPP_UNORDERED_SET
12
13// clang-format off
14
15/*
16
17    unordered_set synopsis
18
19#include <initializer_list>
20
21namespace std
22{
23
24template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
25          class Alloc = allocator<Value>>
26class unordered_set
27{
28public:
29    // types
30    typedef Value                                                      key_type;
31    typedef key_type                                                   value_type;
32    typedef Hash                                                       hasher;
33    typedef Pred                                                       key_equal;
34    typedef Alloc                                                      allocator_type;
35    typedef value_type&                                                reference;
36    typedef const value_type&                                          const_reference;
37    typedef typename allocator_traits<allocator_type>::pointer         pointer;
38    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
39    typedef typename allocator_traits<allocator_type>::size_type       size_type;
40    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
41
42    typedef /unspecified/ iterator;
43    typedef /unspecified/ const_iterator;
44    typedef /unspecified/ local_iterator;
45    typedef /unspecified/ const_local_iterator;
46
47    typedef unspecified node_type unspecified;                            // C++17
48    typedef INSERT_RETURN_TYPE<iterator, node_type> insert_return_type;   // C++17
49
50    unordered_set()
51        noexcept(
52            is_nothrow_default_constructible<hasher>::value &&
53            is_nothrow_default_constructible<key_equal>::value &&
54            is_nothrow_default_constructible<allocator_type>::value);
55    explicit unordered_set(size_type n, const hasher& hf = hasher(),
56                           const key_equal& eql = key_equal(),
57                           const allocator_type& a = allocator_type());
58    template <class InputIterator>
59        unordered_set(InputIterator f, InputIterator l,
60                      size_type n = 0, const hasher& hf = hasher(),
61                      const key_equal& eql = key_equal(),
62                      const allocator_type& a = allocator_type());
63    template<container-compatible-range<value_type> R>
64      unordered_set(from_range_t, R&& rg, size_type n = see below,
65        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
66        const allocator_type& a = allocator_type()); // C++23
67    explicit unordered_set(const allocator_type&);
68    unordered_set(const unordered_set&);
69    unordered_set(const unordered_set&, const Allocator&);
70    unordered_set(unordered_set&&)
71        noexcept(
72            is_nothrow_move_constructible<hasher>::value &&
73            is_nothrow_move_constructible<key_equal>::value &&
74            is_nothrow_move_constructible<allocator_type>::value);
75    unordered_set(unordered_set&&, const Allocator&);
76    unordered_set(initializer_list<value_type>, size_type n = 0,
77                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
78                  const allocator_type& a = allocator_type());
79    unordered_set(size_type n, const allocator_type& a); // C++14
80    unordered_set(size_type n, const hasher& hf, const allocator_type& a); // C++14
81    template <class InputIterator>
82      unordered_set(InputIterator f, InputIterator l, size_type n, const allocator_type& a); // C++14
83    template <class InputIterator>
84      unordered_set(InputIterator f, InputIterator l, size_type n,
85                    const hasher& hf,  const allocator_type& a); // C++14
86    template<container-compatible-range<value_type> R>
87      unordered_set(from_range_t, R&& rg, size_type n, const allocator_type& a)
88        : unordered_set(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
89    template<container-compatible-range<value_type> R>
90      unordered_set(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
91        : unordered_set(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
92    unordered_set(initializer_list<value_type> il, size_type n, const allocator_type& a); // C++14
93    unordered_set(initializer_list<value_type> il, size_type n,
94                  const hasher& hf,  const allocator_type& a); // C++14
95    ~unordered_set();
96    unordered_set& operator=(const unordered_set&);
97    unordered_set& operator=(unordered_set&&)
98        noexcept(
99            allocator_type::propagate_on_container_move_assignment::value &&
100            is_nothrow_move_assignable<allocator_type>::value &&
101            is_nothrow_move_assignable<hasher>::value &&
102            is_nothrow_move_assignable<key_equal>::value);
103    unordered_set& operator=(initializer_list<value_type>);
104
105    allocator_type get_allocator() const noexcept;
106
107    bool      empty() const noexcept;
108    size_type size() const noexcept;
109    size_type max_size() const noexcept;
110
111    iterator       begin() noexcept;
112    iterator       end() noexcept;
113    const_iterator begin()  const noexcept;
114    const_iterator end()    const noexcept;
115    const_iterator cbegin() const noexcept;
116    const_iterator cend()   const noexcept;
117
118    template <class... Args>
119        pair<iterator, bool> emplace(Args&&... args);
120    template <class... Args>
121        iterator emplace_hint(const_iterator position, Args&&... args);
122    pair<iterator, bool> insert(const value_type& obj);
123    pair<iterator, bool> insert(value_type&& obj);
124    iterator insert(const_iterator hint, const value_type& obj);
125    iterator insert(const_iterator hint, value_type&& obj);
126    template <class InputIterator>
127        void insert(InputIterator first, InputIterator last);
128    template<container-compatible-range<value_type> R>
129      void insert_range(R&& rg);                                      // C++23
130    void insert(initializer_list<value_type>);
131
132    node_type extract(const_iterator position);                       // C++17
133    node_type extract(const key_type& x);                             // C++17
134    insert_return_type insert(node_type&& nh);                        // C++17
135    iterator           insert(const_iterator hint, node_type&& nh);   // C++17
136
137    iterator erase(const_iterator position);
138    iterator erase(iterator position);  // C++14
139    size_type erase(const key_type& k);
140    iterator erase(const_iterator first, const_iterator last);
141    void clear() noexcept;
142
143    template<class H2, class P2>
144      void merge(unordered_set<Key, H2, P2, Allocator>& source);         // C++17
145    template<class H2, class P2>
146      void merge(unordered_set<Key, H2, P2, Allocator>&& source);        // C++17
147    template<class H2, class P2>
148      void merge(unordered_multiset<Key, H2, P2, Allocator>& source);    // C++17
149    template<class H2, class P2>
150      void merge(unordered_multiset<Key, H2, P2, Allocator>&& source);   // C++17
151
152    void swap(unordered_set&)
153       noexcept(allocator_traits<Allocator>::is_always_equal::value &&
154                 noexcept(swap(declval<hasher&>(), declval<hasher&>())) &&
155                 noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
156
157    hasher hash_function() const;
158    key_equal key_eq() const;
159
160    iterator       find(const key_type& k);
161    const_iterator find(const key_type& k) const;
162    template<typename K>
163        iterator find(const K& x);              // C++20
164    template<typename K>
165        const_iterator find(const K& x) const;  // C++20
166    size_type count(const key_type& k) const;
167    template<typename K>
168        size_type count(const K& k) const; // C++20
169    bool contains(const key_type& k) const; // C++20
170    template<typename K>
171        bool contains(const K& k) const; // C++20
172    pair<iterator, iterator>             equal_range(const key_type& k);
173    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
174    template<typename K>
175        pair<iterator, iterator>             equal_range(const K& k); // C++20
176    template<typename K>
177        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
178
179    size_type bucket_count() const noexcept;
180    size_type max_bucket_count() const noexcept;
181
182    size_type bucket_size(size_type n) const;
183    size_type bucket(const key_type& k) const;
184
185    local_iterator       begin(size_type n);
186    local_iterator       end(size_type n);
187    const_local_iterator begin(size_type n) const;
188    const_local_iterator end(size_type n) const;
189    const_local_iterator cbegin(size_type n) const;
190    const_local_iterator cend(size_type n) const;
191
192    float load_factor() const noexcept;
193    float max_load_factor() const noexcept;
194    void max_load_factor(float z);
195    void rehash(size_type n);
196    void reserve(size_type n);
197};
198
199template<class InputIterator,
200    class Hash = hash<typename iterator_traits<InputIterator>::value_type>,
201    class Pred = equal_to<typename iterator_traits<InputIterator>::value_type>,
202    class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
203unordered_set(InputIterator, InputIterator, typename see below::size_type = see below,
204    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
205  -> unordered_set<typename iterator_traits<InputIterator>::value_type,
206        Hash, Pred, Allocator>; // C++17
207
208template<ranges::input_range R,
209         class Hash = hash<ranges::range_value_t<R>>,
210         class Pred = equal_to<ranges::range_value_t<R>>,
211         class Allocator = allocator<ranges::range_value_t<R>>>
212  unordered_set(from_range_t, R&&, typename see below::size_type = see below, Hash = Hash(), Pred = Pred(), Allocator = Allocator())
213    -> unordered_set<ranges::range_value_t<R>, Hash, Pred, Allocator>; // C++23
214
215template<class T, class Hash = hash<T>,
216          class Pred = equal_to<T>, class Allocator = allocator<T>>
217unordered_set(initializer_list<T>, typename see below::size_type = see below,
218    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
219  -> unordered_set<T, Hash, Pred, Allocator>; // C++17
220
221template<class InputIterator,  class Allocator>
222unordered_set(InputIterator, InputIterator, typename see below::size_type, Allocator)
223  -> unordered_set<typename iterator_traits<InputIterator>::value_type,
224        hash<typename iterator_traits<InputIterator>::value_type>,
225        equal_to<typename iterator_traits<InputIterator>::value_type>,
226        Allocator>; // C++17
227
228template<class InputIterator, class Hash, class Allocator>
229unordered_set(InputIterator, InputIterator, typename see below::size_type,
230    Hash, Allocator)
231  -> unordered_set<typename iterator_traits<InputIterator>::value_type, Hash,
232        equal_to<typename iterator_traits<InputIterator>::value_type>,
233        Allocator>; // C++17
234
235template<ranges::input_range R, class Allocator>
236  unordered_set(from_range_t, R&&, typename see below::size_type, Allocator)
237    -> unordered_set<ranges::range_value_t<R>, hash<ranges::range_value_t<R>>,
238                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
239
240template<ranges::input_range R, class Allocator>
241  unordered_set(from_range_t, R&&, Allocator)
242    -> unordered_set<ranges::range_value_t<R>, hash<ranges::range_value_t<R>>,
243                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
244
245template<ranges::input_range R, class Hash, class Allocator>
246  unordered_set(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
247    -> unordered_set<ranges::range_value_t<R>, Hash,
248                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
249
250template<class T, class Allocator>
251unordered_set(initializer_list<T>, typename see below::size_type, Allocator)
252  -> unordered_set<T, hash<T>, equal_to<T>, Allocator>; // C++17
253
254template<class T, class Hash, class Allocator>
255unordered_set(initializer_list<T>, typename see below::size_type, Hash, Allocator)
256  -> unordered_set<T, Hash, equal_to<T>, Allocator>; // C++17
257
258template <class Value, class Hash, class Pred, class Alloc>
259    void swap(unordered_set<Value, Hash, Pred, Alloc>& x,
260              unordered_set<Value, Hash, Pred, Alloc>& y)
261              noexcept(noexcept(x.swap(y)));
262
263template <class Value, class Hash, class Pred, class Alloc>
264    bool
265    operator==(const unordered_set<Value, Hash, Pred, Alloc>& x,
266               const unordered_set<Value, Hash, Pred, Alloc>& y);
267
268template <class Value, class Hash, class Pred, class Alloc>
269    bool
270    operator!=(const unordered_set<Value, Hash, Pred, Alloc>& x,
271               const unordered_set<Value, Hash, Pred, Alloc>& y); // removed in C++20
272
273template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
274          class Alloc = allocator<Value>>
275class unordered_multiset
276{
277public:
278    // types
279    typedef Value                                                      key_type;
280    typedef key_type                                                   value_type;
281    typedef Hash                                                       hasher;
282    typedef Pred                                                       key_equal;
283    typedef Alloc                                                      allocator_type;
284    typedef value_type&                                                reference;
285    typedef const value_type&                                          const_reference;
286    typedef typename allocator_traits<allocator_type>::pointer         pointer;
287    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
288    typedef typename allocator_traits<allocator_type>::size_type       size_type;
289    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
290
291    typedef /unspecified/ iterator;
292    typedef /unspecified/ const_iterator;
293    typedef /unspecified/ local_iterator;
294    typedef /unspecified/ const_local_iterator;
295
296    typedef unspecified node_type unspecified;   // C++17
297
298    unordered_multiset()
299        noexcept(
300            is_nothrow_default_constructible<hasher>::value &&
301            is_nothrow_default_constructible<key_equal>::value &&
302            is_nothrow_default_constructible<allocator_type>::value);
303    explicit unordered_multiset(size_type n, const hasher& hf = hasher(),
304                           const key_equal& eql = key_equal(),
305                           const allocator_type& a = allocator_type());
306    template <class InputIterator>
307        unordered_multiset(InputIterator f, InputIterator l,
308                      size_type n = 0, const hasher& hf = hasher(),
309                      const key_equal& eql = key_equal(),
310                      const allocator_type& a = allocator_type());
311    template<container-compatible-range<value_type> R>
312      unordered_multiset(from_range_t, R&& rg, size_type n = see below,
313        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
314        const allocator_type& a = allocator_type()); // C++23
315    explicit unordered_multiset(const allocator_type&);
316    unordered_multiset(const unordered_multiset&);
317    unordered_multiset(const unordered_multiset&, const Allocator&);
318    unordered_multiset(unordered_multiset&&)
319        noexcept(
320            is_nothrow_move_constructible<hasher>::value &&
321            is_nothrow_move_constructible<key_equal>::value &&
322            is_nothrow_move_constructible<allocator_type>::value);
323    unordered_multiset(unordered_multiset&&, const Allocator&);
324    unordered_multiset(initializer_list<value_type>, size_type n = /see below/,
325                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
326                  const allocator_type& a = allocator_type());
327    unordered_multiset(size_type n, const allocator_type& a); // C++14
328    unordered_multiset(size_type n, const hasher& hf, const allocator_type& a); // C++14
329    template <class InputIterator>
330      unordered_multiset(InputIterator f, InputIterator l, size_type n, const allocator_type& a); // C++14
331    template <class InputIterator>
332      unordered_multiset(InputIterator f, InputIterator l, size_type n,
333                         const hasher& hf, const allocator_type& a); // C++14
334    template<container-compatible-range<value_type> R>
335      unordered_multiset(from_range_t, R&& rg, size_type n, const allocator_type& a)
336        : unordered_multiset(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
337    template<container-compatible-range<value_type> R>
338      unordered_multiset(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
339        : unordered_multiset(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
340    unordered_multiset(initializer_list<value_type> il, size_type n, const allocator_type& a); // C++14
341    unordered_multiset(initializer_list<value_type> il, size_type n,
342                       const hasher& hf,  const allocator_type& a); // C++14
343    ~unordered_multiset();
344    unordered_multiset& operator=(const unordered_multiset&);
345    unordered_multiset& operator=(unordered_multiset&&)
346        noexcept(
347            allocator_type::propagate_on_container_move_assignment::value &&
348            is_nothrow_move_assignable<allocator_type>::value &&
349            is_nothrow_move_assignable<hasher>::value &&
350            is_nothrow_move_assignable<key_equal>::value);
351    unordered_multiset& operator=(initializer_list<value_type>);
352
353    allocator_type get_allocator() const noexcept;
354
355    bool      empty() const noexcept;
356    size_type size() const noexcept;
357    size_type max_size() const noexcept;
358
359    iterator       begin() noexcept;
360    iterator       end() noexcept;
361    const_iterator begin()  const noexcept;
362    const_iterator end()    const noexcept;
363    const_iterator cbegin() const noexcept;
364    const_iterator cend()   const noexcept;
365
366    template <class... Args>
367        iterator emplace(Args&&... args);
368    template <class... Args>
369        iterator emplace_hint(const_iterator position, Args&&... args);
370    iterator insert(const value_type& obj);
371    iterator insert(value_type&& obj);
372    iterator insert(const_iterator hint, const value_type& obj);
373    iterator insert(const_iterator hint, value_type&& obj);
374    template <class InputIterator>
375        void insert(InputIterator first, InputIterator last);
376    template<container-compatible-range<value_type> R>
377      void insert_range(R&& rg);                            // C++23
378    void insert(initializer_list<value_type>);
379
380    node_type extract(const_iterator position);             // C++17
381    node_type extract(const key_type& x);                   // C++17
382    iterator insert(node_type&& nh);                        // C++17
383    iterator insert(const_iterator hint, node_type&& nh);   // C++17
384
385    iterator erase(const_iterator position);
386    iterator erase(iterator position);  // C++14
387    size_type erase(const key_type& k);
388    iterator erase(const_iterator first, const_iterator last);
389    void clear() noexcept;
390
391    template<class H2, class P2>
392      void merge(unordered_multiset<Key, H2, P2, Allocator>& source);    // C++17
393    template<class H2, class P2>
394      void merge(unordered_multiset<Key, H2, P2, Allocator>&& source);   // C++17
395    template<class H2, class P2>
396      void merge(unordered_set<Key, H2, P2, Allocator>& source);         // C++17
397    template<class H2, class P2>
398      void merge(unordered_set<Key, H2, P2, Allocator>&& source);        // C++17
399
400    void swap(unordered_multiset&)
401       noexcept(allocator_traits<Allocator>::is_always_equal::value &&
402                 noexcept(swap(declval<hasher&>(), declval<hasher&>())) &&
403                 noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
404
405    hasher hash_function() const;
406    key_equal key_eq() const;
407
408    iterator       find(const key_type& k);
409    const_iterator find(const key_type& k) const;
410    template<typename K>
411        iterator find(const K& x);              // C++20
412    template<typename K>
413        const_iterator find(const K& x) const;  // C++20
414    size_type count(const key_type& k) const;
415    template<typename K>
416        size_type count(const K& k) const; // C++20
417    bool contains(const key_type& k) const; // C++20
418    template<typename K>
419        bool contains(const K& k) const; // C++20
420    pair<iterator, iterator>             equal_range(const key_type& k);
421    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
422    template<typename K>
423        pair<iterator, iterator>             equal_range(const K& k); // C++20
424    template<typename K>
425        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
426
427    size_type bucket_count() const noexcept;
428    size_type max_bucket_count() const noexcept;
429
430    size_type bucket_size(size_type n) const;
431    size_type bucket(const key_type& k) const;
432
433    local_iterator       begin(size_type n);
434    local_iterator       end(size_type n);
435    const_local_iterator begin(size_type n) const;
436    const_local_iterator end(size_type n) const;
437    const_local_iterator cbegin(size_type n) const;
438    const_local_iterator cend(size_type n) const;
439
440    float load_factor() const noexcept;
441    float max_load_factor() const noexcept;
442    void max_load_factor(float z);
443    void rehash(size_type n);
444    void reserve(size_type n);
445};
446
447template<class InputIterator,
448    class Hash = hash<typename iterator_traits<InputIterator>::value_type>,
449    class Pred = equal_to<typename iterator_traits<InputIterator>::value_type>,
450    class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
451unordered_multiset(InputIterator, InputIterator, see below::size_type = see below,
452    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
453  -> unordered_multiset<typename iterator_traits<InputIterator>::value_type,
454        Hash, Pred, Allocator>; // C++17
455
456template<ranges::input_range R,
457         class Hash = hash<ranges::range_value_t<R>>,
458         class Pred = equal_to<ranges::range_value_t<R>>,
459         class Allocator = allocator<ranges::range_value_t<R>>>
460  unordered_multiset(from_range_t, R&&, typename see below::size_type = see below, Hash = Hash(), Pred = Pred(), Allocator = Allocator())
461    -> unordered_multiset<ranges::range_value_t<R>, Hash, Pred, Allocator>; // C++23
462
463template<class T, class Hash = hash<T>,
464          class Pred = equal_to<T>, class Allocator = allocator<T>>
465unordered_multiset(initializer_list<T>, typename see below::size_type = see below,
466    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
467  -> unordered_multiset<T, Hash, Pred, Allocator>; // C++17
468
469template<class InputIterator,  class Allocator>
470unordered_multiset(InputIterator, InputIterator, typename see below::size_type, Allocator)
471  -> unordered_multiset<typename iterator_traits<InputIterator>::value_type,
472        hash<typename iterator_traits<InputIterator>::value_type>,
473        equal_to<typename iterator_traits<InputIterator>::value_type>,
474        Allocator>; // C++17
475
476template<class InputIterator,  class Hash, class Allocator>
477unordered_multiset(InputIterator, InputIterator, typename see below::size_type,
478    Hash, Allocator)
479  -> unordered_multiset<typename iterator_traits<InputIterator>::value_type, Hash,
480        equal_to<typename iterator_traits<InputIterator>::value_type>, Allocator>; // C++17
481
482template<ranges::input_range R, class Allocator>
483  unordered_multiset(from_range_t, R&&, typename see below::size_type, Allocator)
484    -> unordered_multiset<ranges::range_value_t<R>, hash<ranges::range_value_t<R>>,
485                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
486
487template<ranges::input_range R, class Allocator>
488  unordered_multiset(from_range_t, R&&, Allocator)
489    -> unordered_multiset<ranges::range_value_t<R>, hash<ranges::range_value_t<R>>,
490                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
491
492template<ranges::input_range R, class Hash, class Allocator>
493  unordered_multiset(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
494    -> unordered_multiset<ranges::range_value_t<R>, Hash,
495                      equal_to<ranges::range_value_t<R>>, Allocator>; // C++23
496
497template<class T, class Allocator>
498unordered_multiset(initializer_list<T>, typename see below::size_type, Allocator)
499  -> unordered_multiset<T, hash<T>, equal_to<T>, Allocator>; // C++17
500
501template<class T, class Hash, class Allocator>
502unordered_multiset(initializer_list<T>, typename see below::size_type, Hash, Allocator)
503  -> unordered_multiset<T, Hash, equal_to<T>, Allocator>; // C++17
504
505template <class Value, class Hash, class Pred, class Alloc>
506    void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x,
507              unordered_multiset<Value, Hash, Pred, Alloc>& y)
508              noexcept(noexcept(x.swap(y)));
509
510template <class K, class T, class H, class P, class A, class Predicate>
511    typename unordered_set<K, T, H, P, A>::size_type
512    erase_if(unordered_set<K, T, H, P, A>& c, Predicate pred);       // C++20
513
514template <class K, class T, class H, class P, class A, class Predicate>
515    typename unordered_multiset<K, T, H, P, A>::size_type
516    erase_if(unordered_multiset<K, T, H, P, A>& c, Predicate pred);  // C++20
517
518
519template <class Value, class Hash, class Pred, class Alloc>
520    bool
521    operator==(const unordered_multiset<Value, Hash, Pred, Alloc>& x,
522               const unordered_multiset<Value, Hash, Pred, Alloc>& y);
523
524template <class Value, class Hash, class Pred, class Alloc>
525    bool
526    operator!=(const unordered_multiset<Value, Hash, Pred, Alloc>& x,
527               const unordered_multiset<Value, Hash, Pred, Alloc>& y); // removed in C++20
528}  // std
529
530*/
531
532// clang-format on
533
534#include <__algorithm/is_permutation.h>
535#include <__assert>
536#include <__availability>
537#include <__config>
538#include <__functional/is_transparent.h>
539#include <__functional/operations.h>
540#include <__hash_table>
541#include <__iterator/distance.h>
542#include <__iterator/erase_if_container.h>
543#include <__iterator/iterator_traits.h>
544#include <__iterator/ranges_iterator_traits.h>
545#include <__memory/addressof.h>
546#include <__memory/allocator.h>
547#include <__memory_resource/polymorphic_allocator.h>
548#include <__node_handle>
549#include <__ranges/concepts.h>
550#include <__ranges/container_compatible_range.h>
551#include <__ranges/from_range.h>
552#include <__type_traits/is_allocator.h>
553#include <__utility/forward.h>
554#include <version>
555
556// standard-mandated includes
557
558// [iterator.range]
559#include <__iterator/access.h>
560#include <__iterator/data.h>
561#include <__iterator/empty.h>
562#include <__iterator/reverse_access.h>
563#include <__iterator/size.h>
564
565// [unord.set.syn]
566#include <compare>
567#include <initializer_list>
568
569#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
570#  pragma GCC system_header
571#endif
572
573_LIBCPP_PUSH_MACROS
574#include <__undef_macros>
575
576_LIBCPP_BEGIN_NAMESPACE_STD
577
578template <class _Value, class _Hash, class _Pred, class _Alloc>
579class unordered_multiset;
580
581template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>, class _Alloc = allocator<_Value> >
582class _LIBCPP_TEMPLATE_VIS unordered_set {
583public:
584  // types
585  typedef _Value key_type;
586  typedef key_type value_type;
587  typedef __type_identity_t<_Hash> hasher;
588  typedef __type_identity_t<_Pred> key_equal;
589  typedef __type_identity_t<_Alloc> allocator_type;
590  typedef value_type& reference;
591  typedef const value_type& const_reference;
592  static_assert((is_same<value_type, typename allocator_type::value_type>::value),
593                "Allocator::value_type must be same type as value_type");
594
595  static_assert(is_same<allocator_type, __rebind_alloc<allocator_traits<allocator_type>, value_type> >::value,
596                "[allocator.requirements] states that rebinding an allocator to the same type should result in the "
597                "original allocator");
598
599private:
600  typedef __hash_table<value_type, hasher, key_equal, allocator_type> __table;
601
602  __table __table_;
603
604public:
605  typedef typename __table::pointer pointer;
606  typedef typename __table::const_pointer const_pointer;
607  typedef typename __table::size_type size_type;
608  typedef typename __table::difference_type difference_type;
609
610  typedef typename __table::const_iterator iterator;
611  typedef typename __table::const_iterator const_iterator;
612  typedef typename __table::const_local_iterator local_iterator;
613  typedef typename __table::const_local_iterator const_local_iterator;
614
615#if _LIBCPP_STD_VER >= 17
616  typedef __set_node_handle<typename __table::__node, allocator_type> node_type;
617  typedef __insert_return_type<iterator, node_type> insert_return_type;
618#endif
619
620  template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
621  friend class _LIBCPP_TEMPLATE_VIS unordered_set;
622  template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
623  friend class _LIBCPP_TEMPLATE_VIS unordered_multiset;
624
625  _LIBCPP_HIDE_FROM_ABI unordered_set() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
626  explicit _LIBCPP_HIDE_FROM_ABI
627  unordered_set(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
628#if _LIBCPP_STD_VER >= 14
629  inline _LIBCPP_HIDE_FROM_ABI unordered_set(size_type __n, const allocator_type& __a)
630      : unordered_set(__n, hasher(), key_equal(), __a) {}
631  inline _LIBCPP_HIDE_FROM_ABI unordered_set(size_type __n, const hasher& __hf, const allocator_type& __a)
632      : unordered_set(__n, __hf, key_equal(), __a) {}
633#endif
634  _LIBCPP_HIDE_FROM_ABI
635  unordered_set(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
636  template <class _InputIterator>
637  _LIBCPP_HIDE_FROM_ABI unordered_set(_InputIterator __first, _InputIterator __last);
638  template <class _InputIterator>
639  _LIBCPP_HIDE_FROM_ABI
640  unordered_set(_InputIterator __first,
641                _InputIterator __last,
642                size_type __n,
643                const hasher& __hf     = hasher(),
644                const key_equal& __eql = key_equal());
645  template <class _InputIterator>
646  _LIBCPP_HIDE_FROM_ABI unordered_set(
647      _InputIterator __first,
648      _InputIterator __last,
649      size_type __n,
650      const hasher& __hf,
651      const key_equal& __eql,
652      const allocator_type& __a);
653
654#if _LIBCPP_STD_VER >= 23
655  template <_ContainerCompatibleRange<value_type> _Range>
656  _LIBCPP_HIDE_FROM_ABI unordered_set(
657      from_range_t,
658      _Range&& __range,
659      size_type __n             = /*implementation-defined*/ 0,
660      const hasher& __hf        = hasher(),
661      const key_equal& __eql    = key_equal(),
662      const allocator_type& __a = allocator_type())
663      : __table_(__hf, __eql, __a) {
664    if (__n > 0) {
665      __table_.__rehash_unique(__n);
666    }
667    insert_range(std::forward<_Range>(__range));
668  }
669#endif
670
671#if _LIBCPP_STD_VER >= 14
672  template <class _InputIterator>
673  inline _LIBCPP_HIDE_FROM_ABI
674  unordered_set(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
675      : unordered_set(__first, __last, __n, hasher(), key_equal(), __a) {}
676  template <class _InputIterator>
677  _LIBCPP_HIDE_FROM_ABI unordered_set(
678      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
679      : unordered_set(__first, __last, __n, __hf, key_equal(), __a) {}
680#endif
681
682#if _LIBCPP_STD_VER >= 23
683  template <_ContainerCompatibleRange<value_type> _Range>
684  _LIBCPP_HIDE_FROM_ABI unordered_set(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
685      : unordered_set(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}
686
687  template <_ContainerCompatibleRange<value_type> _Range>
688  _LIBCPP_HIDE_FROM_ABI
689  unordered_set(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
690      : unordered_set(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
691#endif
692
693  _LIBCPP_HIDE_FROM_ABI explicit unordered_set(const allocator_type& __a);
694  _LIBCPP_HIDE_FROM_ABI unordered_set(const unordered_set& __u);
695  _LIBCPP_HIDE_FROM_ABI unordered_set(const unordered_set& __u, const allocator_type& __a);
696#ifndef _LIBCPP_CXX03_LANG
697  _LIBCPP_HIDE_FROM_ABI unordered_set(unordered_set&& __u) _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
698  _LIBCPP_HIDE_FROM_ABI unordered_set(unordered_set&& __u, const allocator_type& __a);
699  _LIBCPP_HIDE_FROM_ABI unordered_set(initializer_list<value_type> __il);
700  _LIBCPP_HIDE_FROM_ABI
701  unordered_set(initializer_list<value_type> __il,
702                size_type __n,
703                const hasher& __hf     = hasher(),
704                const key_equal& __eql = key_equal());
705  _LIBCPP_HIDE_FROM_ABI unordered_set(
706      initializer_list<value_type> __il,
707      size_type __n,
708      const hasher& __hf,
709      const key_equal& __eql,
710      const allocator_type& __a);
711#  if _LIBCPP_STD_VER >= 14
712  inline _LIBCPP_HIDE_FROM_ABI
713  unordered_set(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
714      : unordered_set(__il, __n, hasher(), key_equal(), __a) {}
715  inline _LIBCPP_HIDE_FROM_ABI
716  unordered_set(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
717      : unordered_set(__il, __n, __hf, key_equal(), __a) {}
718#  endif
719#endif // _LIBCPP_CXX03_LANG
720  _LIBCPP_HIDE_FROM_ABI ~unordered_set() {
721    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Value, _Hash, _Pred>(0)), "");
722  }
723
724  _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(const unordered_set& __u) {
725    __table_ = __u.__table_;
726    return *this;
727  }
728#ifndef _LIBCPP_CXX03_LANG
729  _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(unordered_set&& __u)
730      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
731  _LIBCPP_HIDE_FROM_ABI unordered_set& operator=(initializer_list<value_type> __il);
732#endif // _LIBCPP_CXX03_LANG
733
734  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
735    return allocator_type(__table_.__node_alloc());
736  }
737
738  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
739  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
740  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
741
742  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
743  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
744  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
745  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
746  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
747  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }
748
749#ifndef _LIBCPP_CXX03_LANG
750  template <class... _Args>
751  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> emplace(_Args&&... __args) {
752    return __table_.__emplace_unique(std::forward<_Args>(__args)...);
753  }
754  template <class... _Args>
755  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator, _Args&&... __args) {
756    return __table_.__emplace_unique(std::forward<_Args>(__args)...).first;
757  }
758
759  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(value_type&& __x) {
760    return __table_.__insert_unique(std::move(__x));
761  }
762  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, value_type&& __x) { return insert(std::move(__x)).first; }
763
764  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }
765#endif // _LIBCPP_CXX03_LANG
766  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(const value_type& __x) { return __table_.__insert_unique(__x); }
767
768  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, const value_type& __x) { return insert(__x).first; }
769  template <class _InputIterator>
770  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);
771
772#if _LIBCPP_STD_VER >= 23
773  template <_ContainerCompatibleRange<value_type> _Range>
774  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
775    for (auto&& __element : __range) {
776      __table_.__insert_unique(std::forward<decltype(__element)>(__element));
777    }
778  }
779#endif
780
781  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p); }
782  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_unique(__k); }
783  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
784    return __table_.erase(__first, __last);
785  }
786  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }
787
788#if _LIBCPP_STD_VER >= 17
789  _LIBCPP_HIDE_FROM_ABI insert_return_type insert(node_type&& __nh) {
790    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
791                                        "node_type with incompatible allocator passed to unordered_set::insert()");
792    return __table_.template __node_handle_insert_unique< node_type, insert_return_type>(std::move(__nh));
793  }
794  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __h, node_type&& __nh) {
795    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
796                                        "node_type with incompatible allocator passed to unordered_set::insert()");
797    return __table_.template __node_handle_insert_unique<node_type>(__h, std::move(__nh));
798  }
799  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
800    return __table_.template __node_handle_extract<node_type>(__key);
801  }
802  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
803    return __table_.template __node_handle_extract<node_type>(__it);
804  }
805
806  template <class _H2, class _P2>
807  _LIBCPP_HIDE_FROM_ABI void merge(unordered_set<key_type, _H2, _P2, allocator_type>& __source) {
808    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
809        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
810    __table_.__node_handle_merge_unique(__source.__table_);
811  }
812  template <class _H2, class _P2>
813  _LIBCPP_HIDE_FROM_ABI void merge(unordered_set<key_type, _H2, _P2, allocator_type>&& __source) {
814    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
815        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
816    __table_.__node_handle_merge_unique(__source.__table_);
817  }
818  template <class _H2, class _P2>
819  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>& __source) {
820    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
821        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
822    __table_.__node_handle_merge_unique(__source.__table_);
823  }
824  template <class _H2, class _P2>
825  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>&& __source) {
826    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
827        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
828    __table_.__node_handle_merge_unique(__source.__table_);
829  }
830#endif
831
832  _LIBCPP_HIDE_FROM_ABI void swap(unordered_set& __u) _NOEXCEPT_(__is_nothrow_swappable<__table>::value) {
833    __table_.swap(__u.__table_);
834  }
835
836  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function(); }
837  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq(); }
838
839  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
840  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
841#if _LIBCPP_STD_VER >= 20
842  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
843  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
844    return __table_.find(__k);
845  }
846  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
847  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
848    return __table_.find(__k);
849  }
850#endif // _LIBCPP_STD_VER >= 20
851
852  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_unique(__k); }
853#if _LIBCPP_STD_VER >= 20
854  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
855  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
856    return __table_.__count_unique(__k);
857  }
858#endif // _LIBCPP_STD_VER >= 20
859
860#if _LIBCPP_STD_VER >= 20
861  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
862
863  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
864  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
865    return find(__k) != end();
866  }
867#endif // _LIBCPP_STD_VER >= 20
868
869  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
870    return __table_.__equal_range_unique(__k);
871  }
872  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
873    return __table_.__equal_range_unique(__k);
874  }
875#if _LIBCPP_STD_VER >= 20
876  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
877  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
878    return __table_.__equal_range_unique(__k);
879  }
880  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
881  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
882    return __table_.__equal_range_unique(__k);
883  }
884#endif // _LIBCPP_STD_VER >= 20
885
886  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
887  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }
888
889  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
890  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }
891
892  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
893  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
894  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
895  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
896  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
897  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }
898
899  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
900  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
901  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
902  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_unique(__n); }
903  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_unique(__n); }
904};
905
906#if _LIBCPP_STD_VER >= 17
907template <class _InputIterator,
908          class _Hash      = hash<__iter_value_type<_InputIterator>>,
909          class _Pred      = equal_to<__iter_value_type<_InputIterator>>,
910          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
911          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
912          class            = enable_if_t<!__is_allocator<_Hash>::value>,
913          class            = enable_if_t<!is_integral<_Hash>::value>,
914          class            = enable_if_t<!__is_allocator<_Pred>::value>,
915          class            = enable_if_t<__is_allocator<_Allocator>::value>>
916unordered_set(_InputIterator,
917              _InputIterator,
918              typename allocator_traits<_Allocator>::size_type = 0,
919              _Hash                                            = _Hash(),
920              _Pred                                            = _Pred(),
921              _Allocator = _Allocator()) -> unordered_set<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
922
923#  if _LIBCPP_STD_VER >= 23
924template <ranges::input_range _Range,
925          class _Hash      = hash<ranges::range_value_t<_Range>>,
926          class _Pred      = equal_to<ranges::range_value_t<_Range>>,
927          class _Allocator = allocator<ranges::range_value_t<_Range>>,
928          class            = enable_if_t<!__is_allocator<_Hash>::value>,
929          class            = enable_if_t<!is_integral<_Hash>::value>,
930          class            = enable_if_t<!__is_allocator<_Pred>::value>,
931          class            = enable_if_t<__is_allocator<_Allocator>::value>>
932unordered_set(from_range_t,
933              _Range&&,
934              typename allocator_traits<_Allocator>::size_type = 0,
935              _Hash                                            = _Hash(),
936              _Pred                                            = _Pred(),
937              _Allocator                                       = _Allocator())
938    -> unordered_set<ranges::range_value_t<_Range>, _Hash, _Pred, _Allocator>; // C++23
939#  endif
940
941template <class _Tp,
942          class _Hash      = hash<_Tp>,
943          class _Pred      = equal_to<_Tp>,
944          class _Allocator = allocator<_Tp>,
945          class            = enable_if_t<!__is_allocator<_Hash>::value>,
946          class            = enable_if_t<!is_integral<_Hash>::value>,
947          class            = enable_if_t<!__is_allocator<_Pred>::value>,
948          class            = enable_if_t<__is_allocator<_Allocator>::value>>
949unordered_set(initializer_list<_Tp>,
950              typename allocator_traits<_Allocator>::size_type = 0,
951              _Hash                                            = _Hash(),
952              _Pred                                            = _Pred(),
953              _Allocator = _Allocator()) -> unordered_set<_Tp, _Hash, _Pred, _Allocator>;
954
955template <class _InputIterator,
956          class _Allocator,
957          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
958          class = enable_if_t<__is_allocator<_Allocator>::value>>
959unordered_set(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
960    -> unordered_set<__iter_value_type<_InputIterator>,
961                     hash<__iter_value_type<_InputIterator>>,
962                     equal_to<__iter_value_type<_InputIterator>>,
963                     _Allocator>;
964
965template <class _InputIterator,
966          class _Hash,
967          class _Allocator,
968          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
969          class = enable_if_t<!__is_allocator<_Hash>::value>,
970          class = enable_if_t<!is_integral<_Hash>::value>,
971          class = enable_if_t<__is_allocator<_Allocator>::value>>
972unordered_set(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
973    -> unordered_set<__iter_value_type<_InputIterator>, _Hash, equal_to<__iter_value_type<_InputIterator>>, _Allocator>;
974
975#  if _LIBCPP_STD_VER >= 23
976
977template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
978unordered_set(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
979    -> unordered_set<ranges::range_value_t<_Range>,
980                     hash<ranges::range_value_t<_Range>>,
981                     equal_to<ranges::range_value_t<_Range>>,
982                     _Allocator>;
983
984template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
985unordered_set(from_range_t, _Range&&, _Allocator)
986    -> unordered_set<ranges::range_value_t<_Range>,
987                     hash<ranges::range_value_t<_Range>>,
988                     equal_to<ranges::range_value_t<_Range>>,
989                     _Allocator>;
990
991template <ranges::input_range _Range,
992          class _Hash,
993          class _Allocator,
994          class = enable_if_t<!__is_allocator<_Hash>::value>,
995          class = enable_if_t<!is_integral<_Hash>::value>,
996          class = enable_if_t<__is_allocator<_Allocator>::value>>
997unordered_set(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
998    -> unordered_set<ranges::range_value_t<_Range>, _Hash, equal_to<ranges::range_value_t<_Range>>, _Allocator>;
999
1000#  endif
1001
1002template <class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1003unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Allocator)
1004    -> unordered_set<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
1005
1006template <class _Tp,
1007          class _Hash,
1008          class _Allocator,
1009          class = enable_if_t<!__is_allocator<_Hash>::value>,
1010          class = enable_if_t<!is_integral<_Hash>::value>,
1011          class = enable_if_t<__is_allocator<_Allocator>::value>>
1012unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1013    -> unordered_set<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
1014#endif
1015
1016template <class _Value, class _Hash, class _Pred, class _Alloc>
1017unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(size_type __n, const hasher& __hf, const key_equal& __eql)
1018    : __table_(__hf, __eql) {
1019  __table_.__rehash_unique(__n);
1020}
1021
1022template <class _Value, class _Hash, class _Pred, class _Alloc>
1023unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
1024    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
1025    : __table_(__hf, __eql, __a) {
1026  __table_.__rehash_unique(__n);
1027}
1028
1029template <class _Value, class _Hash, class _Pred, class _Alloc>
1030template <class _InputIterator>
1031unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(_InputIterator __first, _InputIterator __last) {
1032  insert(__first, __last);
1033}
1034
1035template <class _Value, class _Hash, class _Pred, class _Alloc>
1036template <class _InputIterator>
1037unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
1038    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
1039    : __table_(__hf, __eql) {
1040  __table_.__rehash_unique(__n);
1041  insert(__first, __last);
1042}
1043
1044template <class _Value, class _Hash, class _Pred, class _Alloc>
1045template <class _InputIterator>
1046unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
1047    _InputIterator __first,
1048    _InputIterator __last,
1049    size_type __n,
1050    const hasher& __hf,
1051    const key_equal& __eql,
1052    const allocator_type& __a)
1053    : __table_(__hf, __eql, __a) {
1054  __table_.__rehash_unique(__n);
1055  insert(__first, __last);
1056}
1057
1058template <class _Value, class _Hash, class _Pred, class _Alloc>
1059inline unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(const allocator_type& __a) : __table_(__a) {}
1060
1061template <class _Value, class _Hash, class _Pred, class _Alloc>
1062unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(const unordered_set& __u) : __table_(__u.__table_) {
1063  __table_.__rehash_unique(__u.bucket_count());
1064  insert(__u.begin(), __u.end());
1065}
1066
1067template <class _Value, class _Hash, class _Pred, class _Alloc>
1068unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(const unordered_set& __u, const allocator_type& __a)
1069    : __table_(__u.__table_, __a) {
1070  __table_.__rehash_unique(__u.bucket_count());
1071  insert(__u.begin(), __u.end());
1072}
1073
1074#ifndef _LIBCPP_CXX03_LANG
1075
1076template <class _Value, class _Hash, class _Pred, class _Alloc>
1077inline unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(unordered_set&& __u)
1078    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
1079    : __table_(std::move(__u.__table_)) {}
1080
1081template <class _Value, class _Hash, class _Pred, class _Alloc>
1082unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(unordered_set&& __u, const allocator_type& __a)
1083    : __table_(std::move(__u.__table_), __a) {
1084  if (__a != __u.get_allocator()) {
1085    iterator __i = __u.begin();
1086    while (__u.size() != 0)
1087      __table_.__insert_unique(std::move(__u.__table_.remove(__i++)->__get_value()));
1088  }
1089}
1090
1091template <class _Value, class _Hash, class _Pred, class _Alloc>
1092unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(initializer_list<value_type> __il) {
1093  insert(__il.begin(), __il.end());
1094}
1095
1096template <class _Value, class _Hash, class _Pred, class _Alloc>
1097unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
1098    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
1099    : __table_(__hf, __eql) {
1100  __table_.__rehash_unique(__n);
1101  insert(__il.begin(), __il.end());
1102}
1103
1104template <class _Value, class _Hash, class _Pred, class _Alloc>
1105unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
1106    initializer_list<value_type> __il,
1107    size_type __n,
1108    const hasher& __hf,
1109    const key_equal& __eql,
1110    const allocator_type& __a)
1111    : __table_(__hf, __eql, __a) {
1112  __table_.__rehash_unique(__n);
1113  insert(__il.begin(), __il.end());
1114}
1115
1116template <class _Value, class _Hash, class _Pred, class _Alloc>
1117inline unordered_set<_Value, _Hash, _Pred, _Alloc>&
1118unordered_set<_Value, _Hash, _Pred, _Alloc>::operator=(unordered_set&& __u)
1119    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
1120  __table_ = std::move(__u.__table_);
1121  return *this;
1122}
1123
1124template <class _Value, class _Hash, class _Pred, class _Alloc>
1125inline unordered_set<_Value, _Hash, _Pred, _Alloc>&
1126unordered_set<_Value, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
1127  __table_.__assign_unique(__il.begin(), __il.end());
1128  return *this;
1129}
1130
1131#endif // _LIBCPP_CXX03_LANG
1132
1133template <class _Value, class _Hash, class _Pred, class _Alloc>
1134template <class _InputIterator>
1135inline void unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
1136  for (; __first != __last; ++__first)
1137    __table_.__insert_unique(*__first);
1138}
1139
1140template <class _Value, class _Hash, class _Pred, class _Alloc>
1141inline _LIBCPP_HIDE_FROM_ABI void
1142swap(unordered_set<_Value, _Hash, _Pred, _Alloc>& __x, unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
1143    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
1144  __x.swap(__y);
1145}
1146
1147#if _LIBCPP_STD_VER >= 20
1148template <class _Value, class _Hash, class _Pred, class _Alloc, class _Predicate>
1149inline _LIBCPP_HIDE_FROM_ABI typename unordered_set<_Value, _Hash, _Pred, _Alloc>::size_type
1150erase_if(unordered_set<_Value, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
1151  return std::__libcpp_erase_if_container(__c, __pred);
1152}
1153#endif
1154
1155template <class _Value, class _Hash, class _Pred, class _Alloc>
1156_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
1157                                      const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y) {
1158  if (__x.size() != __y.size())
1159    return false;
1160  typedef typename unordered_set<_Value, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
1161  for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end(); __i != __ex; ++__i) {
1162    const_iterator __j = __y.find(*__i);
1163    if (__j == __ey || !(*__i == *__j))
1164      return false;
1165  }
1166  return true;
1167}
1168
1169#if _LIBCPP_STD_VER <= 17
1170
1171template <class _Value, class _Hash, class _Pred, class _Alloc>
1172inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
1173                                             const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y) {
1174  return !(__x == __y);
1175}
1176
1177#endif
1178
1179template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>, class _Alloc = allocator<_Value> >
1180class _LIBCPP_TEMPLATE_VIS unordered_multiset {
1181public:
1182  // types
1183  typedef _Value key_type;
1184  typedef key_type value_type;
1185  typedef __type_identity_t<_Hash> hasher;
1186  typedef __type_identity_t<_Pred> key_equal;
1187  typedef __type_identity_t<_Alloc> allocator_type;
1188  typedef value_type& reference;
1189  typedef const value_type& const_reference;
1190  static_assert((is_same<value_type, typename allocator_type::value_type>::value),
1191                "Allocator::value_type must be same type as value_type");
1192
1193private:
1194  typedef __hash_table<value_type, hasher, key_equal, allocator_type> __table;
1195
1196  __table __table_;
1197
1198public:
1199  typedef typename __table::pointer pointer;
1200  typedef typename __table::const_pointer const_pointer;
1201  typedef typename __table::size_type size_type;
1202  typedef typename __table::difference_type difference_type;
1203
1204  typedef typename __table::const_iterator iterator;
1205  typedef typename __table::const_iterator const_iterator;
1206  typedef typename __table::const_local_iterator local_iterator;
1207  typedef typename __table::const_local_iterator const_local_iterator;
1208
1209#if _LIBCPP_STD_VER >= 17
1210  typedef __set_node_handle<typename __table::__node, allocator_type> node_type;
1211#endif
1212
1213  template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
1214  friend class _LIBCPP_TEMPLATE_VIS unordered_set;
1215  template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
1216  friend class _LIBCPP_TEMPLATE_VIS unordered_multiset;
1217
1218  _LIBCPP_HIDE_FROM_ABI unordered_multiset() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
1219  explicit _LIBCPP_HIDE_FROM_ABI
1220  unordered_multiset(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
1221  _LIBCPP_HIDE_FROM_ABI
1222  unordered_multiset(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
1223#if _LIBCPP_STD_VER >= 14
1224  inline _LIBCPP_HIDE_FROM_ABI unordered_multiset(size_type __n, const allocator_type& __a)
1225      : unordered_multiset(__n, hasher(), key_equal(), __a) {}
1226  inline _LIBCPP_HIDE_FROM_ABI unordered_multiset(size_type __n, const hasher& __hf, const allocator_type& __a)
1227      : unordered_multiset(__n, __hf, key_equal(), __a) {}
1228#endif
1229  template <class _InputIterator>
1230  _LIBCPP_HIDE_FROM_ABI unordered_multiset(_InputIterator __first, _InputIterator __last);
1231  template <class _InputIterator>
1232  _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1233      _InputIterator __first,
1234      _InputIterator __last,
1235      size_type __n,
1236      const hasher& __hf     = hasher(),
1237      const key_equal& __eql = key_equal());
1238  template <class _InputIterator>
1239  _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1240      _InputIterator __first,
1241      _InputIterator __last,
1242      size_type __n,
1243      const hasher& __hf,
1244      const key_equal& __eql,
1245      const allocator_type& __a);
1246
1247#if _LIBCPP_STD_VER >= 23
1248  template <_ContainerCompatibleRange<value_type> _Range>
1249  _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1250      from_range_t,
1251      _Range&& __range,
1252      size_type __n             = /*implementation-defined*/ 0,
1253      const hasher& __hf        = hasher(),
1254      const key_equal& __eql    = key_equal(),
1255      const allocator_type& __a = allocator_type())
1256      : __table_(__hf, __eql, __a) {
1257    if (__n > 0) {
1258      __table_.__rehash_multi(__n);
1259    }
1260    insert_range(std::forward<_Range>(__range));
1261  }
1262#endif
1263
1264#if _LIBCPP_STD_VER >= 14
1265  template <class _InputIterator>
1266  inline _LIBCPP_HIDE_FROM_ABI
1267  unordered_multiset(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
1268      : unordered_multiset(__first, __last, __n, hasher(), key_equal(), __a) {}
1269  template <class _InputIterator>
1270  inline _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1271      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
1272      : unordered_multiset(__first, __last, __n, __hf, key_equal(), __a) {}
1273#endif
1274
1275#if _LIBCPP_STD_VER >= 23
1276  template <_ContainerCompatibleRange<value_type> _Range>
1277  _LIBCPP_HIDE_FROM_ABI unordered_multiset(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
1278      : unordered_multiset(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}
1279
1280  template <_ContainerCompatibleRange<value_type> _Range>
1281  _LIBCPP_HIDE_FROM_ABI
1282  unordered_multiset(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
1283      : unordered_multiset(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
1284#endif
1285
1286  _LIBCPP_HIDE_FROM_ABI explicit unordered_multiset(const allocator_type& __a);
1287  _LIBCPP_HIDE_FROM_ABI unordered_multiset(const unordered_multiset& __u);
1288  _LIBCPP_HIDE_FROM_ABI unordered_multiset(const unordered_multiset& __u, const allocator_type& __a);
1289#ifndef _LIBCPP_CXX03_LANG
1290  _LIBCPP_HIDE_FROM_ABI unordered_multiset(unordered_multiset&& __u)
1291      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
1292  _LIBCPP_HIDE_FROM_ABI unordered_multiset(unordered_multiset&& __u, const allocator_type& __a);
1293  _LIBCPP_HIDE_FROM_ABI unordered_multiset(initializer_list<value_type> __il);
1294  _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1295      initializer_list<value_type> __il,
1296      size_type __n,
1297      const hasher& __hf     = hasher(),
1298      const key_equal& __eql = key_equal());
1299  _LIBCPP_HIDE_FROM_ABI unordered_multiset(
1300      initializer_list<value_type> __il,
1301      size_type __n,
1302      const hasher& __hf,
1303      const key_equal& __eql,
1304      const allocator_type& __a);
1305#  if _LIBCPP_STD_VER >= 14
1306  inline _LIBCPP_HIDE_FROM_ABI
1307  unordered_multiset(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
1308      : unordered_multiset(__il, __n, hasher(), key_equal(), __a) {}
1309  inline _LIBCPP_HIDE_FROM_ABI
1310  unordered_multiset(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
1311      : unordered_multiset(__il, __n, __hf, key_equal(), __a) {}
1312#  endif
1313#endif // _LIBCPP_CXX03_LANG
1314  _LIBCPP_HIDE_FROM_ABI ~unordered_multiset() {
1315    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Value, _Hash, _Pred>(0)), "");
1316  }
1317
1318  _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(const unordered_multiset& __u) {
1319    __table_ = __u.__table_;
1320    return *this;
1321  }
1322#ifndef _LIBCPP_CXX03_LANG
1323  _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(unordered_multiset&& __u)
1324      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
1325  _LIBCPP_HIDE_FROM_ABI unordered_multiset& operator=(initializer_list<value_type> __il);
1326#endif // _LIBCPP_CXX03_LANG
1327
1328  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
1329    return allocator_type(__table_.__node_alloc());
1330  }
1331
1332  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
1333  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
1334  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
1335
1336  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
1337  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
1338  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
1339  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
1340  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
1341  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }
1342
1343#ifndef _LIBCPP_CXX03_LANG
1344  template <class... _Args>
1345  _LIBCPP_HIDE_FROM_ABI iterator emplace(_Args&&... __args) {
1346    return __table_.__emplace_multi(std::forward<_Args>(__args)...);
1347  }
1348  template <class... _Args>
1349  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator __p, _Args&&... __args) {
1350    return __table_.__emplace_hint_multi(__p, std::forward<_Args>(__args)...);
1351  }
1352
1353  _LIBCPP_HIDE_FROM_ABI iterator insert(value_type&& __x) { return __table_.__insert_multi(std::move(__x)); }
1354  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __x) {
1355    return __table_.__insert_multi(__p, std::move(__x));
1356  }
1357  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }
1358#endif // _LIBCPP_CXX03_LANG
1359
1360  _LIBCPP_HIDE_FROM_ABI iterator insert(const value_type& __x) { return __table_.__insert_multi(__x); }
1361
1362  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x) {
1363    return __table_.__insert_multi(__p, __x);
1364  }
1365
1366  template <class _InputIterator>
1367  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);
1368
1369#if _LIBCPP_STD_VER >= 23
1370  template <_ContainerCompatibleRange<value_type> _Range>
1371  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
1372    for (auto&& __element : __range) {
1373      __table_.__insert_multi(std::forward<decltype(__element)>(__element));
1374    }
1375  }
1376#endif
1377
1378#if _LIBCPP_STD_VER >= 17
1379  _LIBCPP_HIDE_FROM_ABI iterator insert(node_type&& __nh) {
1380    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
1381                                        "node_type with incompatible allocator passed to unordered_multiset::insert()");
1382    return __table_.template __node_handle_insert_multi<node_type>(std::move(__nh));
1383  }
1384  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __hint, node_type&& __nh) {
1385    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
1386                                        "node_type with incompatible allocator passed to unordered_multiset::insert()");
1387    return __table_.template __node_handle_insert_multi<node_type>(__hint, std::move(__nh));
1388  }
1389  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __position) {
1390    return __table_.template __node_handle_extract<node_type>(__position);
1391  }
1392  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
1393    return __table_.template __node_handle_extract<node_type>(__key);
1394  }
1395
1396  template <class _H2, class _P2>
1397  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>& __source) {
1398    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1399        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1400    return __table_.__node_handle_merge_multi(__source.__table_);
1401  }
1402  template <class _H2, class _P2>
1403  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>&& __source) {
1404    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1405        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1406    return __table_.__node_handle_merge_multi(__source.__table_);
1407  }
1408  template <class _H2, class _P2>
1409  _LIBCPP_HIDE_FROM_ABI void merge(unordered_set<key_type, _H2, _P2, allocator_type>& __source) {
1410    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1411        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1412    return __table_.__node_handle_merge_multi(__source.__table_);
1413  }
1414  template <class _H2, class _P2>
1415  _LIBCPP_HIDE_FROM_ABI void merge(unordered_set<key_type, _H2, _P2, allocator_type>&& __source) {
1416    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1417        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1418    return __table_.__node_handle_merge_multi(__source.__table_);
1419  }
1420#endif
1421
1422  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p); }
1423  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_multi(__k); }
1424  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
1425    return __table_.erase(__first, __last);
1426  }
1427  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }
1428
1429  _LIBCPP_HIDE_FROM_ABI void swap(unordered_multiset& __u) _NOEXCEPT_(__is_nothrow_swappable<__table>::value) {
1430    __table_.swap(__u.__table_);
1431  }
1432
1433  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function(); }
1434  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq(); }
1435
1436  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
1437  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
1438#if _LIBCPP_STD_VER >= 20
1439  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1440  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
1441    return __table_.find(__k);
1442  }
1443  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1444  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
1445    return __table_.find(__k);
1446  }
1447#endif // _LIBCPP_STD_VER >= 20
1448
1449  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_multi(__k); }
1450#if _LIBCPP_STD_VER >= 20
1451  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1452  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
1453    return __table_.__count_multi(__k);
1454  }
1455#endif // _LIBCPP_STD_VER >= 20
1456
1457#if _LIBCPP_STD_VER >= 20
1458  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
1459
1460  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1461  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
1462    return find(__k) != end();
1463  }
1464#endif // _LIBCPP_STD_VER >= 20
1465
1466  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
1467    return __table_.__equal_range_multi(__k);
1468  }
1469  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
1470    return __table_.__equal_range_multi(__k);
1471  }
1472#if _LIBCPP_STD_VER >= 20
1473  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1474  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
1475    return __table_.__equal_range_multi(__k);
1476  }
1477  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1478  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
1479    return __table_.__equal_range_multi(__k);
1480  }
1481#endif // _LIBCPP_STD_VER >= 20
1482
1483  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
1484  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }
1485
1486  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
1487  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }
1488
1489  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
1490  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
1491  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
1492  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
1493  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
1494  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }
1495
1496  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
1497  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
1498  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
1499  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_multi(__n); }
1500  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_multi(__n); }
1501};
1502
1503#if _LIBCPP_STD_VER >= 17
1504template <class _InputIterator,
1505          class _Hash      = hash<__iter_value_type<_InputIterator>>,
1506          class _Pred      = equal_to<__iter_value_type<_InputIterator>>,
1507          class _Allocator = allocator<__iter_value_type<_InputIterator>>,
1508          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1509          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1510          class            = enable_if_t<!is_integral<_Hash>::value>,
1511          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1512          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1513unordered_multiset(
1514    _InputIterator,
1515    _InputIterator,
1516    typename allocator_traits<_Allocator>::size_type = 0,
1517    _Hash                                            = _Hash(),
1518    _Pred                                            = _Pred(),
1519    _Allocator = _Allocator()) -> unordered_multiset<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
1520
1521#  if _LIBCPP_STD_VER >= 23
1522template <ranges::input_range _Range,
1523          class _Hash      = hash<ranges::range_value_t<_Range>>,
1524          class _Pred      = equal_to<ranges::range_value_t<_Range>>,
1525          class _Allocator = allocator<ranges::range_value_t<_Range>>,
1526          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1527          class            = enable_if_t<!is_integral<_Hash>::value>,
1528          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1529          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1530unordered_multiset(
1531    from_range_t,
1532    _Range&&,
1533    typename allocator_traits<_Allocator>::size_type = 0,
1534    _Hash                                            = _Hash(),
1535    _Pred                                            = _Pred(),
1536    _Allocator = _Allocator()) -> unordered_multiset<ranges::range_value_t<_Range>, _Hash, _Pred, _Allocator>; // C++23
1537#  endif
1538
1539template <class _Tp,
1540          class _Hash      = hash<_Tp>,
1541          class _Pred      = equal_to<_Tp>,
1542          class _Allocator = allocator<_Tp>,
1543          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1544          class            = enable_if_t<!is_integral<_Hash>::value>,
1545          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1546          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1547unordered_multiset(initializer_list<_Tp>,
1548                   typename allocator_traits<_Allocator>::size_type = 0,
1549                   _Hash                                            = _Hash(),
1550                   _Pred                                            = _Pred(),
1551                   _Allocator = _Allocator()) -> unordered_multiset<_Tp, _Hash, _Pred, _Allocator>;
1552
1553template <class _InputIterator,
1554          class _Allocator,
1555          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1556          class = enable_if_t<__is_allocator<_Allocator>::value>>
1557unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
1558    -> unordered_multiset<__iter_value_type<_InputIterator>,
1559                          hash<__iter_value_type<_InputIterator>>,
1560                          equal_to<__iter_value_type<_InputIterator>>,
1561                          _Allocator>;
1562
1563template <class _InputIterator,
1564          class _Hash,
1565          class _Allocator,
1566          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1567          class = enable_if_t<!__is_allocator<_Hash>::value>,
1568          class = enable_if_t<!is_integral<_Hash>::value>,
1569          class = enable_if_t<__is_allocator<_Allocator>::value>>
1570unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1571    -> unordered_multiset<__iter_value_type<_InputIterator>,
1572                          _Hash,
1573                          equal_to<__iter_value_type<_InputIterator>>,
1574                          _Allocator>;
1575
1576#  if _LIBCPP_STD_VER >= 23
1577
1578template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1579unordered_multiset(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
1580    -> unordered_multiset<ranges::range_value_t<_Range>,
1581                          hash<ranges::range_value_t<_Range>>,
1582                          equal_to<ranges::range_value_t<_Range>>,
1583                          _Allocator>;
1584
1585template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1586unordered_multiset(from_range_t, _Range&&, _Allocator)
1587    -> unordered_multiset<ranges::range_value_t<_Range>,
1588                          hash<ranges::range_value_t<_Range>>,
1589                          equal_to<ranges::range_value_t<_Range>>,
1590                          _Allocator>;
1591
1592template <ranges::input_range _Range,
1593          class _Hash,
1594          class _Allocator,
1595          class = enable_if_t<!__is_allocator<_Hash>::value>,
1596          class = enable_if_t<!is_integral<_Hash>::value>,
1597          class = enable_if_t<__is_allocator<_Allocator>::value>>
1598unordered_multiset(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1599    -> unordered_multiset<ranges::range_value_t<_Range>, _Hash, equal_to<ranges::range_value_t<_Range>>, _Allocator>;
1600
1601#  endif
1602
1603template <class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1604unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Allocator)
1605    -> unordered_multiset<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
1606
1607template <class _Tp,
1608          class _Hash,
1609          class _Allocator,
1610          class = enable_if_t<!__is_allocator<_Hash>::value>,
1611          class = enable_if_t<!is_integral<_Hash>::value>,
1612          class = enable_if_t<__is_allocator<_Allocator>::value>>
1613unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1614    -> unordered_multiset<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
1615#endif
1616
1617template <class _Value, class _Hash, class _Pred, class _Alloc>
1618unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1619    size_type __n, const hasher& __hf, const key_equal& __eql)
1620    : __table_(__hf, __eql) {
1621  __table_.__rehash_multi(__n);
1622}
1623
1624template <class _Value, class _Hash, class _Pred, class _Alloc>
1625unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1626    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
1627    : __table_(__hf, __eql, __a) {
1628  __table_.__rehash_multi(__n);
1629}
1630
1631template <class _Value, class _Hash, class _Pred, class _Alloc>
1632template <class _InputIterator>
1633unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(_InputIterator __first, _InputIterator __last) {
1634  insert(__first, __last);
1635}
1636
1637template <class _Value, class _Hash, class _Pred, class _Alloc>
1638template <class _InputIterator>
1639unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1640    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
1641    : __table_(__hf, __eql) {
1642  __table_.__rehash_multi(__n);
1643  insert(__first, __last);
1644}
1645
1646template <class _Value, class _Hash, class _Pred, class _Alloc>
1647template <class _InputIterator>
1648unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1649    _InputIterator __first,
1650    _InputIterator __last,
1651    size_type __n,
1652    const hasher& __hf,
1653    const key_equal& __eql,
1654    const allocator_type& __a)
1655    : __table_(__hf, __eql, __a) {
1656  __table_.__rehash_multi(__n);
1657  insert(__first, __last);
1658}
1659
1660template <class _Value, class _Hash, class _Pred, class _Alloc>
1661inline unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(const allocator_type& __a)
1662    : __table_(__a) {}
1663
1664template <class _Value, class _Hash, class _Pred, class _Alloc>
1665unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(const unordered_multiset& __u)
1666    : __table_(__u.__table_) {
1667  __table_.__rehash_multi(__u.bucket_count());
1668  insert(__u.begin(), __u.end());
1669}
1670
1671template <class _Value, class _Hash, class _Pred, class _Alloc>
1672unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1673    const unordered_multiset& __u, const allocator_type& __a)
1674    : __table_(__u.__table_, __a) {
1675  __table_.__rehash_multi(__u.bucket_count());
1676  insert(__u.begin(), __u.end());
1677}
1678
1679#ifndef _LIBCPP_CXX03_LANG
1680
1681template <class _Value, class _Hash, class _Pred, class _Alloc>
1682inline unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(unordered_multiset&& __u)
1683    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
1684    : __table_(std::move(__u.__table_)) {}
1685
1686template <class _Value, class _Hash, class _Pred, class _Alloc>
1687unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1688    unordered_multiset&& __u, const allocator_type& __a)
1689    : __table_(std::move(__u.__table_), __a) {
1690  if (__a != __u.get_allocator()) {
1691    iterator __i = __u.begin();
1692    while (__u.size() != 0)
1693      __table_.__insert_multi(std::move(__u.__table_.remove(__i++)->__get_value()));
1694  }
1695}
1696
1697template <class _Value, class _Hash, class _Pred, class _Alloc>
1698unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(initializer_list<value_type> __il) {
1699  insert(__il.begin(), __il.end());
1700}
1701
1702template <class _Value, class _Hash, class _Pred, class _Alloc>
1703unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1704    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
1705    : __table_(__hf, __eql) {
1706  __table_.__rehash_multi(__n);
1707  insert(__il.begin(), __il.end());
1708}
1709
1710template <class _Value, class _Hash, class _Pred, class _Alloc>
1711unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
1712    initializer_list<value_type> __il,
1713    size_type __n,
1714    const hasher& __hf,
1715    const key_equal& __eql,
1716    const allocator_type& __a)
1717    : __table_(__hf, __eql, __a) {
1718  __table_.__rehash_multi(__n);
1719  insert(__il.begin(), __il.end());
1720}
1721
1722template <class _Value, class _Hash, class _Pred, class _Alloc>
1723inline unordered_multiset<_Value, _Hash, _Pred, _Alloc>&
1724unordered_multiset<_Value, _Hash, _Pred, _Alloc>::operator=(unordered_multiset&& __u)
1725    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
1726  __table_ = std::move(__u.__table_);
1727  return *this;
1728}
1729
1730template <class _Value, class _Hash, class _Pred, class _Alloc>
1731inline unordered_multiset<_Value, _Hash, _Pred, _Alloc>&
1732unordered_multiset<_Value, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
1733  __table_.__assign_multi(__il.begin(), __il.end());
1734  return *this;
1735}
1736
1737#endif // _LIBCPP_CXX03_LANG
1738
1739template <class _Value, class _Hash, class _Pred, class _Alloc>
1740template <class _InputIterator>
1741inline void unordered_multiset<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
1742  for (; __first != __last; ++__first)
1743    __table_.__insert_multi(*__first);
1744}
1745
1746template <class _Value, class _Hash, class _Pred, class _Alloc>
1747inline _LIBCPP_HIDE_FROM_ABI void
1748swap(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x, unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
1749    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
1750  __x.swap(__y);
1751}
1752
1753#if _LIBCPP_STD_VER >= 20
1754template <class _Value, class _Hash, class _Pred, class _Alloc, class _Predicate>
1755inline _LIBCPP_HIDE_FROM_ABI typename unordered_multiset<_Value, _Hash, _Pred, _Alloc>::size_type
1756erase_if(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
1757  return std::__libcpp_erase_if_container(__c, __pred);
1758}
1759#endif
1760
1761template <class _Value, class _Hash, class _Pred, class _Alloc>
1762_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
1763                                      const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y) {
1764  if (__x.size() != __y.size())
1765    return false;
1766  typedef typename unordered_multiset<_Value, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
1767  typedef pair<const_iterator, const_iterator> _EqRng;
1768  for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;) {
1769    _EqRng __xeq = __x.equal_range(*__i);
1770    _EqRng __yeq = __y.equal_range(*__i);
1771    if (std::distance(__xeq.first, __xeq.second) != std::distance(__yeq.first, __yeq.second) ||
1772        !std::is_permutation(__xeq.first, __xeq.second, __yeq.first))
1773      return false;
1774    __i = __xeq.second;
1775  }
1776  return true;
1777}
1778
1779#if _LIBCPP_STD_VER <= 17
1780
1781template <class _Value, class _Hash, class _Pred, class _Alloc>
1782inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
1783                                             const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y) {
1784  return !(__x == __y);
1785}
1786
1787#endif
1788
1789_LIBCPP_END_NAMESPACE_STD
1790
1791#if _LIBCPP_STD_VER >= 17
1792_LIBCPP_BEGIN_NAMESPACE_STD
1793namespace pmr {
1794template <class _KeyT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
1795using unordered_set _LIBCPP_AVAILABILITY_PMR = std::unordered_set<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
1796
1797template <class _KeyT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
1798using unordered_multiset _LIBCPP_AVAILABILITY_PMR =
1799    std::unordered_multiset<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
1800} // namespace pmr
1801_LIBCPP_END_NAMESPACE_STD
1802#endif
1803
1804_LIBCPP_POP_MACROS
1805
1806#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1807#  include <concepts>
1808#  include <cstdlib>
1809#  include <functional>
1810#  include <iterator>
1811#  include <stdexcept>
1812#  include <type_traits>
1813#endif
1814
1815#endif // _LIBCPP_UNORDERED_SET
1816