[libc++][ranges] implement `std::ranges::set_symmetric_difference`

[libc++][ranges] implement `std::ranges::set_symmetric_difference`

Differential Revision: https://reviews.llvm.org/D129520

1 files changed, 21 insertions, 0 deletions

diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 18d8ef3..f616a03 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -692,6 +692,26 @@ namespace ranges {
       ranges::find_end(R1&& r1, R2&& r2, Pred pred = {},
                        Proj1 proj1 = {}, Proj2 proj2 = {});                                         // since C++20
 
+  template<class I1, class I2, class O>
+    using set_symmetric_difference_result = in_in_out_result<I1, I2, O>;                            // since C++20
+
+  template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
+           weakly_incrementable O, class Comp = ranges::less,
+           class Proj1 = identity, class Proj2 = identity>
+    requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
+    constexpr set_symmetric_difference_result<I1, I2, O>
+      set_symmetric_difference(I1 first1, S1 last1, I2 first2, S2 last2, O result,
+                               Comp comp = {}, Proj1 proj1 = {},
+                               Proj2 proj2 = {});                                                   // since C++20
+  
+  template<input_range R1, input_range R2, weakly_incrementable O,
+           class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
+    requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
+    constexpr set_symmetric_difference_result<borrowed_iterator_t<R1>,
+                                                      borrowed_iterator_t<R2>, O>
+      set_symmetric_difference(R1&& r1, R2&& r2, O result, Comp comp = {},
+                               Proj1 proj1 = {}, Proj2 proj2 = {});                                 // since C++20
+  
 }
 
     constexpr bool     // constexpr in C++20
@@ -1472,6 +1492,7 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/ranges_search_n.h>
 #include <__algorithm/ranges_set_difference.h>
 #include <__algorithm/ranges_set_intersection.h>
+#include <__algorithm/ranges_set_symmetric_difference.h>
 #include <__algorithm/ranges_sort.h>
 #include <__algorithm/ranges_sort_heap.h>
 #include <__algorithm/ranges_stable_sort.h>