21     heap.pop();  in simple_test()
28     heap.pop();  in simple_test()
31     heap.pop();  in simple_test()
39     heap.pop();  in simple_test()
42     heap.pop();  in simple_test()
45     heap.pop();  in simple_test()
54     heap.pop();  in simple_test()
57     heap.pop();  in simple_test()
60     heap.pop();  in simple_test()
63     heap.pop();  in simple_test()
96                 array.pop();  in random_test()
126                     pq.pop();  in random_test()
196         pqControl.pop();  in sort_test()
197         pqTest.pop();  in sort_test()