[libc++][ranges] Implement `ranges::{prev, next}_permutation`.
Co-authored-by: Konstantin Varlamov <[email protected]>
Differential Revision: https://reviews.llvm.org/D129859
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 15ba340..6da0146 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -993,8 +993,39 @@
replace_copy_if(R&& r, O result, Pred pred, const T& new_value,
Proj proj = {}); // Since C++20
+ template<class I>
+ using prev_permutation_result = in_found_result<I>; // Since C++20
+
+ template<bidirectional_iterator I, sentinel_for<I> S, class Comp = ranges::less,
+ class Proj = identity>
+ requires sortable<I, Comp, Proj>
+ constexpr ranges::prev_permutation_result<I>
+ ranges::prev_permutation(I first, S last, Comp comp = {}, Proj proj = {}); // Since C++20
+
+ template<bidirectional_range R, class Comp = ranges::less,
+ class Proj = identity>
+ requires sortable<iterator_t<R>, Comp, Proj>
+ constexpr ranges::prev_permutation_result<borrowed_iterator_t<R>>
+ ranges::prev_permutation(R&& r, Comp comp = {}, Proj proj = {}); // Since C++20
+
+ template<class I>
+ using next_permutation_result = in_found_result<I>; // Since C++20
+
+ template<bidirectional_iterator I, sentinel_for<I> S, class Comp = ranges::less,
+ class Proj = identity>
+ requires sortable<I, Comp, Proj>
+ constexpr ranges::next_permutation_result<I>
+ ranges::next_permutation(I first, S last, Comp comp = {}, Proj proj = {}); // Since C++20
+
+ template<bidirectional_range R, class Comp = ranges::less,
+ class Proj = identity>
+ requires sortable<iterator_t<R>, Comp, Proj>
+ constexpr ranges::next_permutation_result<borrowed_iterator_t<R>>
+ ranges::next_permutation(R&& r, Comp comp = {}, Proj proj = {}); // Since C++20
+
}
+template <class InputIterator, class Predicate>
constexpr bool // constexpr in C++20
all_of(InputIterator first, InputIterator last, Predicate pred);
@@ -1765,6 +1796,7 @@
#include <__algorithm/ranges_mismatch.h>
#include <__algorithm/ranges_move.h>
#include <__algorithm/ranges_move_backward.h>
+#include <__algorithm/ranges_next_permutation.h>
#include <__algorithm/ranges_none_of.h>
#include <__algorithm/ranges_nth_element.h>
#include <__algorithm/ranges_partial_sort.h>
@@ -1773,6 +1805,7 @@
#include <__algorithm/ranges_partition_copy.h>
#include <__algorithm/ranges_partition_point.h>
#include <__algorithm/ranges_pop_heap.h>
+#include <__algorithm/ranges_prev_permutation.h>
#include <__algorithm/ranges_push_heap.h>
#include <__algorithm/ranges_remove.h>
#include <__algorithm/ranges_remove_copy.h>
