push_heap.h 3.0 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_PUSH_HEAP_H
  9. #define _LIBCPP___ALGORITHM_PUSH_HEAP_H
  10. #include <__algorithm/comp.h>
  11. #include <__algorithm/comp_ref_type.h>
  12. #include <__algorithm/iterator_operations.h>
  13. #include <__config>
  14. #include <__iterator/iterator_traits.h>
  15. #include <__type_traits/is_copy_assignable.h>
  16. #include <__type_traits/is_copy_constructible.h>
  17. #include <__utility/move.h>
  18. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  19. # pragma GCC system_header
  20. #endif
  21. _LIBCPP_PUSH_MACROS
  22. #include <__undef_macros>
  23. _LIBCPP_BEGIN_NAMESPACE_STD
  24. template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
  25. _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
  26. void __sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp,
  27. typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
  28. using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
  29. if (__len > 1) {
  30. __len = (__len - 2) / 2;
  31. _RandomAccessIterator __ptr = __first + __len;
  32. if (__comp(*__ptr, *--__last)) {
  33. value_type __t(_IterOps<_AlgPolicy>::__iter_move(__last));
  34. do {
  35. *__last = _IterOps<_AlgPolicy>::__iter_move(__ptr);
  36. __last = __ptr;
  37. if (__len == 0)
  38. break;
  39. __len = (__len - 1) / 2;
  40. __ptr = __first + __len;
  41. } while (__comp(*__ptr, __t));
  42. *__last = std::move(__t);
  43. }
  44. }
  45. }
  46. template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
  47. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
  48. void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
  49. typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
  50. std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
  51. }
  52. template <class _RandomAccessIterator, class _Compare>
  53. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  54. void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  55. static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
  56. static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
  57. std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
  58. }
  59. template <class _RandomAccessIterator>
  60. inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  61. void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  62. std::push_heap(std::move(__first), std::move(__last), __less<>());
  63. }
  64. _LIBCPP_END_NAMESPACE_STD
  65. _LIBCPP_POP_MACROS
  66. #endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H