--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libcxx/include/__algorithm/ranges_nth_element.h	Wed Nov 09 17:45:10 2022 +0900
@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_NTH_ELEMENT_H
+#define _LIBCPP___ALGORITHM_RANGES_NTH_ELEMENT_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/make_projected.h>
+#include <__algorithm/nth_element.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/projected.h>
+#include <__iterator/sortable.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __nth_element {
+
+struct __fn {
+  template <class _Iter, class _Sent, class _Comp, class _Proj>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  _Iter __nth_element_fn_impl(_Iter __first, _Iter __nth, _Sent __last, _Comp& __comp, _Proj& __proj) {
+    auto __last_iter = ranges::next(__first, __last);
+
+    auto&& __projected_comp = std::__make_projected(__comp, __proj);
+    std::__nth_element_impl<_RangeAlgPolicy>(std::move(__first), std::move(__nth), __last_iter, __projected_comp);
+
+    return __last_iter;
+  }
+
+  template <random_access_iterator _Iter, sentinel_for<_Iter> _Sent, class _Comp = ranges::less, class _Proj = identity>
+    requires sortable<_Iter, _Comp, _Proj>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  _Iter operator()(_Iter __first, _Iter __nth, _Sent __last, _Comp __comp = {}, _Proj __proj = {}) const {
+    return __nth_element_fn_impl(std::move(__first), std::move(__nth), std::move(__last), __comp, __proj);
+  }
+
+  template <random_access_range _Range, class _Comp = ranges::less, class _Proj = identity>
+    requires sortable<iterator_t<_Range>, _Comp, _Proj>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_iterator_t<_Range> operator()(_Range&& __r, iterator_t<_Range> __nth, _Comp __comp = {},
+                                         _Proj __proj = {}) const {
+    return __nth_element_fn_impl(ranges::begin(__r), std::move(__nth), ranges::end(__r), __comp, __proj);
+  }
+};
+
+} // namespace __nth_element
+
+inline namespace __cpo {
+  inline constexpr auto nth_element = __nth_element::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17
+
+#endif // _LIBCPP___ALGORITHM_RANGES_NTH_ELEMENT_H