diff options
Diffstat (limited to 'libcxx/include/__algorithm/partial_sort.h')
| -rw-r--r-- | libcxx/include/__algorithm/partial_sort.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/libcxx/include/__algorithm/partial_sort.h b/libcxx/include/__algorithm/partial_sort.h index 622624ec4f42..a92a7e56610a 100644 --- a/libcxx/include/__algorithm/partial_sort.h +++ b/libcxx/include/__algorithm/partial_sort.h @@ -9,12 +9,12 @@ #ifndef _LIBCPP___ALGORITHM_PARTIAL_SORT_H #define _LIBCPP___ALGORITHM_PARTIAL_SORT_H -#include <__config> #include <__algorithm/comp.h> #include <__algorithm/comp_ref_type.h> #include <__algorithm/make_heap.h> #include <__algorithm/sift_down.h> #include <__algorithm/sort_heap.h> +#include <__config> #include <__iterator/iterator_traits.h> #include <__utility/swap.h> @@ -31,8 +31,10 @@ _LIBCPP_BEGIN_NAMESPACE_STD template <class _Compare, class _RandomAccessIterator> _LIBCPP_CONSTEXPR_AFTER_CXX17 void __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, - _Compare __comp) + _Compare __comp) { + if (__first == __middle) + return; _VSTD::__make_heap<_Compare>(__first, __middle, __comp); typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first; for (_RandomAccessIterator __i = __middle; __i != __last; ++__i) @@ -40,7 +42,7 @@ __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _R if (__comp(*__i, *__first)) { swap(*__i, *__first); - _VSTD::__sift_down<_Compare>(__first, __middle, __comp, __len, __first); + _VSTD::__sift_down<_Compare>(__first, __comp, __len, __first); } } _VSTD::__sort_heap<_Compare>(__first, __middle, __comp); @@ -64,7 +66,7 @@ void partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) { _VSTD::partial_sort(__first, __middle, __last, - __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); + __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); } _LIBCPP_END_NAMESPACE_STD |