pop_heap.h 2.9 KB

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  1. //===----------------------------------------------------------------------===//
  2. //
  3. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  4. // See https://llvm.org/LICENSE.txt for license information.
  5. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  6. //
  7. //===----------------------------------------------------------------------===//
  8. #ifndef _LIBCPP___ALGORITHM_POP_HEAP_H
  9. #define _LIBCPP___ALGORITHM_POP_HEAP_H
  10. #include <__algorithm/comp.h>
  11. #include <__algorithm/comp_ref_type.h>
  12. #include <__algorithm/iterator_operations.h>
  13. #include <__algorithm/push_heap.h>
  14. #include <__algorithm/sift_down.h>
  15. #include <__assert>
  16. #include <__config>
  17. #include <__iterator/iterator_traits.h>
  18. #include <__type_traits/is_copy_assignable.h>
  19. #include <__type_traits/is_copy_constructible.h>
  20. #include <__utility/move.h>
  21. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  22. # pragma GCC system_header
  23. #endif
  24. _LIBCPP_PUSH_MACROS
  25. #include <__undef_macros>
  26. _LIBCPP_BEGIN_NAMESPACE_STD
  27. template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
  28. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
  29. void __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp,
  30. typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
  31. _LIBCPP_ASSERT_UNCATEGORIZED(__len > 0, "The heap given to pop_heap must be non-empty");
  32. __comp_ref_type<_Compare> __comp_ref = __comp;
  33. using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
  34. if (__len > 1) {
  35. value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first); // create a hole at __first
  36. _RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len);
  37. --__last;
  38. if (__hole == __last) {
  39. *__hole = std::move(__top);
  40. } else {
  41. *__hole = _IterOps<_AlgPolicy>::__iter_move(__last);
  42. ++__hole;
  43. *__last = std::move(__top);
  44. std::__sift_up<_AlgPolicy>(__first, __hole, __comp_ref, __hole - __first);
  45. }
  46. }
  47. }
  48. template <class _RandomAccessIterator, class _Compare>
  49. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  50. void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  51. static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
  52. static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
  53. typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
  54. std::__pop_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp, __len);
  55. }
  56. template <class _RandomAccessIterator>
  57. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  58. void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  59. std::pop_heap(std::move(__first), std::move(__last), __less<>());
  60. }
  61. _LIBCPP_END_NAMESPACE_STD
  62. _LIBCPP_POP_MACROS
  63. #endif // _LIBCPP___ALGORITHM_POP_HEAP_H