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 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // 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___CXX03___TREE
 #define _LIBCPP___CXX03___TREE
 
 #include <__cxx03/__algorithm/min.h>
 #include <__cxx03/__assert>
 #include <__cxx03/__config>
 #include <__cxx03/__functional/invoke.h>
 #include <__cxx03/__iterator/distance.h>
 #include <__cxx03/__iterator/iterator_traits.h>
 #include <__cxx03/__iterator/next.h>
 #include <__cxx03/__memory/addressof.h>
 #include <__cxx03/__memory/allocator_traits.h>
 #include <__cxx03/__memory/compressed_pair.h>
 #include <__cxx03/__memory/pointer_traits.h>
 #include <__cxx03/__memory/swap_allocator.h>
 #include <__cxx03/__memory/unique_ptr.h>
 #include <__cxx03/__type_traits/can_extract_key.h>
 #include <__cxx03/__type_traits/conditional.h>
 #include <__cxx03/__type_traits/is_const.h>
 #include <__cxx03/__type_traits/is_constructible.h>
 #include <__cxx03/__type_traits/is_nothrow_assignable.h>
 #include <__cxx03/__type_traits/is_nothrow_constructible.h>
 #include <__cxx03/__type_traits/is_pointer.h>
 #include <__cxx03/__type_traits/is_same.h>
 #include <__cxx03/__type_traits/is_swappable.h>
 #include <__cxx03/__type_traits/remove_const_ref.h>
 #include <__cxx03/__type_traits/remove_cvref.h>
 #include <__cxx03/__utility/forward.h>
 #include <__cxx03/__utility/move.h>
 #include <__cxx03/__utility/pair.h>
 #include <__cxx03/__utility/swap.h>
 #include <__cxx03/limits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__cxx03/__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class, class, class, class>
 class _LIBCPP_TEMPLATE_VIS map;
 template <class, class, class, class>
 class _LIBCPP_TEMPLATE_VIS multimap;
 template <class, class, class>
 class _LIBCPP_TEMPLATE_VIS set;
 template <class, class, class>
 class _LIBCPP_TEMPLATE_VIS multiset;
 
 template <class _Tp, class _Compare, class _Allocator>
 class __tree;
 template <class _Tp, class _NodePtr, class _DiffType>
 class _LIBCPP_TEMPLATE_VIS __tree_iterator;
 template <class _Tp, class _ConstNodePtr, class _DiffType>
 class _LIBCPP_TEMPLATE_VIS __tree_const_iterator;
 
 template <class _Pointer>
 class __tree_end_node;
 template <class _VoidPtr>
 class __tree_node_base;
 template <class _Tp, class _VoidPtr>
 class __tree_node;
 
 template <class _Key, class _Value>
 struct __value_type;
 
 template <class _Allocator>
 class __map_node_destructor;
 template <class _TreeIterator>
 class _LIBCPP_TEMPLATE_VIS __map_iterator;
 template <class _TreeIterator>
 class _LIBCPP_TEMPLATE_VIS __map_const_iterator;
 
 /*
 
 _NodePtr algorithms
 
 The algorithms taking _NodePtr are red black tree algorithms.  Those
 algorithms taking a parameter named __root should assume that __root
 points to a proper red black tree (unless otherwise specified).
 
 Each algorithm herein assumes that __root->__parent_ points to a non-null
 structure which has a member __left_ which points back to __root.  No other
 member is read or written to at __root->__parent_.
 
 __root->__parent_ will be referred to below (in comments only) as end_node.
 end_node->__left_ is an externably accessible lvalue for __root, and can be
 changed by node insertion and removal (without explicit reference to end_node).
 
 All nodes (with the exception of end_node), even the node referred to as
 __root, have a non-null __parent_ field.
 
 */
 
 // Returns:  true if __x is a left child of its parent, else false
 // Precondition:  __x != nullptr.
 template <class _NodePtr>
 inline _LIBCPP_HIDE_FROM_ABI bool __tree_is_left_child(_NodePtr __x) _NOEXCEPT {
   return __x == __x->__parent_->__left_;
 }
 
 // Determines if the subtree rooted at __x is a proper red black subtree.  If
 //    __x is a proper subtree, returns the black height (null counts as 1).  If
 //    __x is an improper subtree, returns 0.
 template <class _NodePtr>
 unsigned __tree_sub_invariant(_NodePtr __x) {
   if (__x == nullptr)
     return 1;
   // parent consistency checked by caller
   // check __x->__left_ consistency
   if (__x->__left_ != nullptr && __x->__left_->__parent_ != __x)
     return 0;
   // check __x->__right_ consistency
   if (__x->__right_ != nullptr && __x->__right_->__parent_ != __x)
     return 0;
   // check __x->__left_ != __x->__right_ unless both are nullptr
   if (__x->__left_ == __x->__right_ && __x->__left_ != nullptr)
     return 0;
   // If this is red, neither child can be red
   if (!__x->__is_black_) {
     if (__x->__left_ && !__x->__left_->__is_black_)
       return 0;
     if (__x->__right_ && !__x->__right_->__is_black_)
       return 0;
   }
   unsigned __h = std::__tree_sub_invariant(__x->__left_);
   if (__h == 0)
     return 0; // invalid left subtree
   if (__h != std::__tree_sub_invariant(__x->__right_))
     return 0;                    // invalid or different height right subtree
   return __h + __x->__is_black_; // return black height of this node
 }
 
 // Determines if the red black tree rooted at __root is a proper red black tree.
 //    __root == nullptr is a proper tree.  Returns true is __root is a proper
 //    red black tree, else returns false.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI bool __tree_invariant(_NodePtr __root) {
   if (__root == nullptr)
     return true;
   // check __x->__parent_ consistency
   if (__root->__parent_ == nullptr)
     return false;
   if (!std::__tree_is_left_child(__root))
     return false;
   // root must be black
   if (!__root->__is_black_)
     return false;
   // do normal node checks
   return std::__tree_sub_invariant(__root) != 0;
 }
 
 // Returns:  pointer to the left-most node under __x.
 template <class _NodePtr>
 inline _LIBCPP_HIDE_FROM_ABI _NodePtr __tree_min(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "Root node shouldn't be null");
   while (__x->__left_ != nullptr)
     __x = __x->__left_;
   return __x;
 }
 
 // Returns:  pointer to the right-most node under __x.
 template <class _NodePtr>
 inline _LIBCPP_HIDE_FROM_ABI _NodePtr __tree_max(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "Root node shouldn't be null");
   while (__x->__right_ != nullptr)
     __x = __x->__right_;
   return __x;
 }
 
 // Returns:  pointer to the next in-order node after __x.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI _NodePtr __tree_next(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   if (__x->__right_ != nullptr)
     return std::__tree_min(__x->__right_);
   while (!std::__tree_is_left_child(__x))
     __x = __x->__parent_unsafe();
   return __x->__parent_unsafe();
 }
 
 template <class _EndNodePtr, class _NodePtr>
 inline _LIBCPP_HIDE_FROM_ABI _EndNodePtr __tree_next_iter(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   if (__x->__right_ != nullptr)
     return static_cast<_EndNodePtr>(std::__tree_min(__x->__right_));
   while (!std::__tree_is_left_child(__x))
     __x = __x->__parent_unsafe();
   return static_cast<_EndNodePtr>(__x->__parent_);
 }
 
 // Returns:  pointer to the previous in-order node before __x.
 // Note: __x may be the end node.
 template <class _NodePtr, class _EndNodePtr>
 inline _LIBCPP_HIDE_FROM_ABI _NodePtr __tree_prev_iter(_EndNodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   if (__x->__left_ != nullptr)
     return std::__tree_max(__x->__left_);
   _NodePtr __xx = static_cast<_NodePtr>(__x);
   while (std::__tree_is_left_child(__xx))
     __xx = __xx->__parent_unsafe();
   return __xx->__parent_unsafe();
 }
 
 // Returns:  pointer to a node which has no children
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI _NodePtr __tree_leaf(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   while (true) {
     if (__x->__left_ != nullptr) {
       __x = __x->__left_;
       continue;
     }
     if (__x->__right_ != nullptr) {
       __x = __x->__right_;
       continue;
     }
     break;
   }
   return __x;
 }
 
 // Effects:  Makes __x->__right_ the subtree root with __x as its left child
 //           while preserving in-order order.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI void __tree_left_rotate(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   _LIBCPP_ASSERT_INTERNAL(__x->__right_ != nullptr, "node should have a right child");
   _NodePtr __y  = __x->__right_;
   __x->__right_ = __y->__left_;
   if (__x->__right_ != nullptr)
     __x->__right_->__set_parent(__x);
   __y->__parent_ = __x->__parent_;
   if (std::__tree_is_left_child(__x))
     __x->__parent_->__left_ = __y;
   else
     __x->__parent_unsafe()->__right_ = __y;
   __y->__left_ = __x;
   __x->__set_parent(__y);
 }
 
 // Effects:  Makes __x->__left_ the subtree root with __x as its right child
 //           while preserving in-order order.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI void __tree_right_rotate(_NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "node shouldn't be null");
   _LIBCPP_ASSERT_INTERNAL(__x->__left_ != nullptr, "node should have a left child");
   _NodePtr __y = __x->__left_;
   __x->__left_ = __y->__right_;
   if (__x->__left_ != nullptr)
     __x->__left_->__set_parent(__x);
   __y->__parent_ = __x->__parent_;
   if (std::__tree_is_left_child(__x))
     __x->__parent_->__left_ = __y;
   else
     __x->__parent_unsafe()->__right_ = __y;
   __y->__right_ = __x;
   __x->__set_parent(__y);
 }
 
 // Effects:  Rebalances __root after attaching __x to a leaf.
 // Precondition:  __x has no children.
 //                __x == __root or == a direct or indirect child of __root.
 //                If __x were to be unlinked from __root (setting __root to
 //                  nullptr if __root == __x), __tree_invariant(__root) == true.
 // Postcondition: __tree_invariant(end_node->__left_) == true.  end_node->__left_
 //                may be different than the value passed in as __root.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI void __tree_balance_after_insert(_NodePtr __root, _NodePtr __x) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__root != nullptr, "Root of the tree shouldn't be null");
   _LIBCPP_ASSERT_INTERNAL(__x != nullptr, "Can't attach null node to a leaf");
   __x->__is_black_ = __x == __root;
   while (__x != __root && !__x->__parent_unsafe()->__is_black_) {
     // __x->__parent_ != __root because __x->__parent_->__is_black == false
     if (std::__tree_is_left_child(__x->__parent_unsafe())) {
       _NodePtr __y = __x->__parent_unsafe()->__parent_unsafe()->__right_;
       if (__y != nullptr && !__y->__is_black_) {
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = true;
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = __x == __root;
         __y->__is_black_ = true;
       } else {
         if (!std::__tree_is_left_child(__x)) {
           __x = __x->__parent_unsafe();
           std::__tree_left_rotate(__x);
         }
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = true;
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = false;
         std::__tree_right_rotate(__x);
         break;
       }
     } else {
       _NodePtr __y = __x->__parent_unsafe()->__parent_->__left_;
       if (__y != nullptr && !__y->__is_black_) {
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = true;
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = __x == __root;
         __y->__is_black_ = true;
       } else {
         if (std::__tree_is_left_child(__x)) {
           __x = __x->__parent_unsafe();
           std::__tree_right_rotate(__x);
         }
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = true;
         __x              = __x->__parent_unsafe();
         __x->__is_black_ = false;
         std::__tree_left_rotate(__x);
         break;
       }
     }
   }
 }
 
 // Precondition:  __z == __root or == a direct or indirect child of __root.
 // Effects:  unlinks __z from the tree rooted at __root, rebalancing as needed.
 // Postcondition: __tree_invariant(end_node->__left_) == true && end_node->__left_
 //                nor any of its children refer to __z.  end_node->__left_
 //                may be different than the value passed in as __root.
 template <class _NodePtr>
 _LIBCPP_HIDE_FROM_ABI void __tree_remove(_NodePtr __root, _NodePtr __z) _NOEXCEPT {
   _LIBCPP_ASSERT_INTERNAL(__root != nullptr, "Root node should not be null");
   _LIBCPP_ASSERT_INTERNAL(__z != nullptr, "The node to remove should not be null");
   _LIBCPP_ASSERT_INTERNAL(std::__tree_invariant(__root), "The tree invariants should hold");
   // __z will be removed from the tree.  Client still needs to destruct/deallocate it
   // __y is either __z, or if __z has two children, __tree_next(__z).
   // __y will have at most one child.
   // __y will be the initial hole in the tree (make the hole at a leaf)
   _NodePtr __y = (__z->__left_ == nullptr || __z->__right_ == nullptr) ? __z : std::__tree_next(__z);
   // __x is __y's possibly null single child
   _NodePtr __x = __y->__left_ != nullptr ? __y->__left_ : __y->__right_;
   // __w is __x's possibly null uncle (will become __x's sibling)
   _NodePtr __w = nullptr;
   // link __x to __y's parent, and find __w
   if (__x != nullptr)
     __x->__parent_ = __y->__parent_;
   if (std::__tree_is_left_child(__y)) {
     __y->__parent_->__left_ = __x;
     if (__y != __root)
       __w = __y->__parent_unsafe()->__right_;
     else
       __root = __x; // __w == nullptr
   } else {
     __y->__parent_unsafe()->__right_ = __x;
     // __y can't be root if it is a right child
     __w = __y->__parent_->__left_;
   }
   bool __removed_black = __y->__is_black_;
   // If we didn't remove __z, do so now by splicing in __y for __z,
   //    but copy __z's color.  This does not impact __x or __w.
   if (__y != __z) {
     // __z->__left_ != nulptr but __z->__right_ might == __x == nullptr
     __y->__parent_ = __z->__parent_;
     if (std::__tree_is_left_child(__z))
       __y->__parent_->__left_ = __y;
     else
       __y->__parent_unsafe()->__right_ = __y;
     __y->__left_ = __z->__left_;
     __y->__left_->__set_parent(__y);
     __y->__right_ = __z->__right_;
     if (__y->__right_ != nullptr)
       __y->__right_->__set_parent(__y);
     __y->__is_black_ = __z->__is_black_;
     if (__root == __z)
       __root = __y;
   }
   // There is no need to rebalance if we removed a red, or if we removed
   //     the last node.
   if (__removed_black && __root != nullptr) {
     // Rebalance:
     // __x has an implicit black color (transferred from the removed __y)
     //    associated with it, no matter what its color is.
     // If __x is __root (in which case it can't be null), it is supposed
     //    to be black anyway, and if it is doubly black, then the double
     //    can just be ignored.
     // If __x is red (in which case it can't be null), then it can absorb
     //    the implicit black just by setting its color to black.
     // Since __y was black and only had one child (which __x points to), __x
     //   is either red with no children, else null, otherwise __y would have
     //   different black heights under left and right pointers.
     // if (__x == __root || __x != nullptr && !__x->__is_black_)
     if (__x != nullptr)
       __x->__is_black_ = true;
     else {
       //  Else __x isn't root, and is "doubly black", even though it may
       //     be null.  __w can not be null here, else the parent would
       //     see a black height >= 2 on the __x side and a black height
       //     of 1 on the __w side (__w must be a non-null black or a red
       //     with a non-null black child).
       while (true) {
         if (!std::__tree_is_left_child(__w)) // if x is left child
         {
           if (!__w->__is_black_) {
             __w->__is_black_                    = true;
             __w->__parent_unsafe()->__is_black_ = false;
             std::__tree_left_rotate(__w->__parent_unsafe());
             // __x is still valid
             // reset __root only if necessary
             if (__root == __w->__left_)
               __root = __w;
             // reset sibling, and it still can't be null
             __w = __w->__left_->__right_;
           }
           // __w->__is_black_ is now true, __w may have null children
           if ((__w->__left_ == nullptr || __w->__left_->__is_black_) &&
               (__w->__right_ == nullptr || __w->__right_->__is_black_)) {
             __w->__is_black_ = false;
             __x              = __w->__parent_unsafe();
             // __x can no longer be null
             if (__x == __root || !__x->__is_black_) {
               __x->__is_black_ = true;
               break;
             }
             // reset sibling, and it still can't be null
             __w = std::__tree_is_left_child(__x) ? __x->__parent_unsafe()->__right_ : __x->__parent_->__left_;
             // continue;
           } else // __w has a red child
           {
             if (__w->__right_ == nullptr || __w->__right_->__is_black_) {
               // __w left child is non-null and red
               __w->__left_->__is_black_ = true;
               __w->__is_black_          = false;
               std::__tree_right_rotate(__w);
               // __w is known not to be root, so root hasn't changed
               // reset sibling, and it still can't be null
               __w = __w->__parent_unsafe();
             }
             // __w has a right red child, left child may be null
             __w->__is_black_                    = __w->__parent_unsafe()->__is_black_;
             __w->__parent_unsafe()->__is_black_ = true;
             __w->__right_->__is_black_          = true;
             std::__tree_left_rotate(__w->__parent_unsafe());
             break;
           }
         } else {
           if (!__w->__is_black_) {
             __w->__is_black_                    = true;
             __w->__parent_unsafe()->__is_black_ = false;
             std::__tree_right_rotate(__w->__parent_unsafe());
             // __x is still valid
             // reset __root only if necessary
             if (__root == __w->__right_)
               __root = __w;
             // reset sibling, and it still can't be null
             __w = __w->__right_->__left_;
           }
           // __w->__is_black_ is now true, __w may have null children
           if ((__w->__left_ == nullptr || __w->__left_->__is_black_) &&
               (__w->__right_ == nullptr || __w->__right_->__is_black_)) {
             __w->__is_black_ = false;
             __x              = __w->__parent_unsafe();
             // __x can no longer be null
             if (!__x->__is_black_ || __x == __root) {
               __x->__is_black_ = true;
               break;
             }
             // reset sibling, and it still can't be null
             __w = std::__tree_is_left_child(__x) ? __x->__parent_unsafe()->__right_ : __x->__parent_->__left_;
             // continue;
           } else // __w has a red child
           {
             if (__w->__left_ == nullptr || __w->__left_->__is_black_) {
               // __w right child is non-null and red
               __w->__right_->__is_black_ = true;
               __w->__is_black_           = false;
               std::__tree_left_rotate(__w);
               // __w is known not to be root, so root hasn't changed
               // reset sibling, and it still can't be null
               __w = __w->__parent_unsafe();
             }
             // __w has a left red child, right child may be null
             __w->__is_black_                    = __w->__parent_unsafe()->__is_black_;
             __w->__parent_unsafe()->__is_black_ = true;
             __w->__left_->__is_black_           = true;
             std::__tree_right_rotate(__w->__parent_unsafe());
             break;
           }
         }
       }
     }
   }
 }
 
 // node traits
 
 template <class _Tp>
 struct __is_tree_value_type_imp : false_type {};
 
 template <class _Key, class _Value>
 struct __is_tree_value_type_imp<__value_type<_Key, _Value> > : true_type {};
 
 template <class... _Args>
 struct __is_tree_value_type : false_type {};
 
 template <class _One>
 struct __is_tree_value_type<_One> : __is_tree_value_type_imp<__remove_cvref_t<_One> > {};
 
 template <class _Tp>
 struct __tree_key_value_types {
   typedef _Tp key_type;
   typedef _Tp __node_value_type;
   typedef _Tp __container_value_type;
   static const bool __is_map = false;
 
   _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(_Tp const& __v) { return __v; }
   _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(__node_value_type const& __v) { return __v; }
   _LIBCPP_HIDE_FROM_ABI static __container_value_type* __get_ptr(__node_value_type& __n) { return std::addressof(__n); }
   _LIBCPP_HIDE_FROM_ABI static __container_value_type&& __move(__node_value_type& __v) { return std::move(__v); }
 };
 
 template <class _Key, class _Tp>
 struct __tree_key_value_types<__value_type<_Key, _Tp> > {
   typedef _Key key_type;
   typedef _Tp mapped_type;
   typedef __value_type<_Key, _Tp> __node_value_type;
   typedef pair<const _Key, _Tp> __container_value_type;
   typedef __container_value_type __map_value_type;
   static const bool __is_map = true;
 
   _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(__node_value_type const& __t) {
     return __t.__get_value().first;
   }
 
   template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(_Up& __t) {
     return __t.first;
   }
 
   _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(__node_value_type const& __t) {
     return __t.__get_value();
   }
 
   template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(_Up& __t) {
     return __t;
   }
 
   _LIBCPP_HIDE_FROM_ABI static __container_value_type* __get_ptr(__node_value_type& __n) {
     return std::addressof(__n.__get_value());
   }
 
   _LIBCPP_HIDE_FROM_ABI static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) { return __v.__move(); }
 };
 
 template <class _VoidPtr>
 struct __tree_node_base_types {
   typedef _VoidPtr __void_pointer;
 
   typedef __tree_node_base<__void_pointer> __node_base_type;
   typedef __rebind_pointer_t<_VoidPtr, __node_base_type> __node_base_pointer;
 
   typedef __tree_end_node<__node_base_pointer> __end_node_type;
   typedef __rebind_pointer_t<_VoidPtr, __end_node_type> __end_node_pointer;
 #if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
   typedef __end_node_pointer __parent_pointer;
 #else
   typedef __conditional_t< is_pointer<__end_node_pointer>::value, __end_node_pointer, __node_base_pointer>
       __parent_pointer;
 #endif
 
 private:
   static_assert(is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value,
                 "_VoidPtr does not point to unqualified void type");
 };
 
 template <class _Tp, class _AllocPtr, class _KVTypes = __tree_key_value_types<_Tp>, bool = _KVTypes::__is_map>
 struct __tree_map_pointer_types {};
 
 template <class _Tp, class _AllocPtr, class _KVTypes>
 struct __tree_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
   typedef typename _KVTypes::__map_value_type _Mv;
   typedef __rebind_pointer_t<_AllocPtr, _Mv> __map_value_type_pointer;
   typedef __rebind_pointer_t<_AllocPtr, const _Mv> __const_map_value_type_pointer;
 };
 
 template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
 struct __tree_node_types;
 
 template <class _NodePtr, class _Tp, class _VoidPtr>
 struct __tree_node_types<_NodePtr, __tree_node<_Tp, _VoidPtr> >
     : public __tree_node_base_types<_VoidPtr>, __tree_key_value_types<_Tp>, __tree_map_pointer_types<_Tp, _VoidPtr> {
   typedef __tree_node_base_types<_VoidPtr> __base;
   typedef __tree_key_value_types<_Tp> __key_base;
   typedef __tree_map_pointer_types<_Tp, _VoidPtr> __map_pointer_base;
 
 public:
   typedef typename pointer_traits<_NodePtr>::element_type __node_type;
   typedef _NodePtr __node_pointer;
 
   typedef _Tp __node_value_type;
   typedef __rebind_pointer_t<_VoidPtr, __node_value_type> __node_value_type_pointer;
   typedef __rebind_pointer_t<_VoidPtr, const __node_value_type> __const_node_value_type_pointer;
 #if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
   typedef typename __base::__end_node_pointer __iter_pointer;
 #else
   typedef __conditional_t< is_pointer<__node_pointer>::value, typename __base::__end_node_pointer, __node_pointer>
       __iter_pointer;
 #endif
 
 private:
   static_assert(!is_const<__node_type>::value, "_NodePtr should never be a pointer to const");
   static_assert(is_same<__rebind_pointer_t<_VoidPtr, __node_type>, _NodePtr>::value,
                 "_VoidPtr does not rebind to _NodePtr.");
 };
 
 template <class _ValueTp, class _VoidPtr>
 struct __make_tree_node_types {
   typedef __rebind_pointer_t<_VoidPtr, __tree_node<_ValueTp, _VoidPtr> > _NodePtr;
   typedef __tree_node_types<_NodePtr> type;
 };
 
 // node
 
 template <class _Pointer>
 class __tree_end_node {
 public:
   typedef _Pointer pointer;
   pointer __left_;
 
   _LIBCPP_HIDE_FROM_ABI __tree_end_node() _NOEXCEPT : __left_() {}
 };
 
 template <class _VoidPtr>
 class _LIBCPP_STANDALONE_DEBUG __tree_node_base : public __tree_node_base_types<_VoidPtr>::__end_node_type {
   typedef __tree_node_base_types<_VoidPtr> _NodeBaseTypes;
 
 public:
   typedef typename _NodeBaseTypes::__node_base_pointer pointer;
   typedef typename _NodeBaseTypes::__parent_pointer __parent_pointer;
 
   pointer __right_;
   __parent_pointer __parent_;
   bool __is_black_;
 
   _LIBCPP_HIDE_FROM_ABI pointer __parent_unsafe() const { return static_cast<pointer>(__parent_); }
 
   _LIBCPP_HIDE_FROM_ABI void __set_parent(pointer __p) { __parent_ = static_cast<__parent_pointer>(__p); }
 
   ~__tree_node_base()                                  = delete;
   __tree_node_base(__tree_node_base const&)            = delete;
   __tree_node_base& operator=(__tree_node_base const&) = delete;
 };
 
 template <class _Tp, class _VoidPtr>
 class _LIBCPP_STANDALONE_DEBUG __tree_node : public __tree_node_base<_VoidPtr> {
 public:
   typedef _Tp __node_value_type;
 
   __node_value_type __value_;
 
   _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return __value_; }
 
   ~__tree_node()                             = delete;
   __tree_node(__tree_node const&)            = delete;
   __tree_node& operator=(__tree_node const&) = delete;
 };
 
 template <class _Allocator>
 class __tree_node_destructor {
   typedef _Allocator allocator_type;
   typedef allocator_traits<allocator_type> __alloc_traits;
 
 public:
   typedef typename __alloc_traits::pointer pointer;
 
 private:
   typedef __tree_node_types<pointer> _NodeTypes;
   allocator_type& __na_;
 
 public:
   bool __value_constructed;
 
   _LIBCPP_HIDE_FROM_ABI __tree_node_destructor(const __tree_node_destructor&) = default;
   __tree_node_destructor& operator=(const __tree_node_destructor&)            = delete;
 
   _LIBCPP_HIDE_FROM_ABI explicit __tree_node_destructor(allocator_type& __na, bool __val = false) _NOEXCEPT
       : __na_(__na),
         __value_constructed(__val) {}
 
   _LIBCPP_HIDE_FROM_ABI void operator()(pointer __p) _NOEXCEPT {
     if (__value_constructed)
       __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
     if (__p)
       __alloc_traits::deallocate(__na_, __p, 1);
   }
 
   template <class>
   friend class __map_node_destructor;
 };
 
 #if _LIBCPP_STD_VER >= 17
 template <class _NodeType, class _Alloc>
 struct __generic_container_node_destructor;
 template <class _Tp, class _VoidPtr, class _Alloc>
 struct __generic_container_node_destructor<__tree_node<_Tp, _VoidPtr>, _Alloc> : __tree_node_destructor<_Alloc> {
   using __tree_node_destructor<_Alloc>::__tree_node_destructor;
 };
 #endif
 
 template <class _Tp, class _NodePtr, class _DiffType>
 class _LIBCPP_TEMPLATE_VIS __tree_iterator {
   typedef __tree_node_types<_NodePtr> _NodeTypes;
   typedef _NodePtr __node_pointer;
   typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
   typedef typename _NodeTypes::__end_node_pointer __end_node_pointer;
   typedef typename _NodeTypes::__iter_pointer __iter_pointer;
   typedef pointer_traits<__node_pointer> __pointer_traits;
 
   __iter_pointer __ptr_;
 
 public:
   typedef bidirectional_iterator_tag iterator_category;
   typedef _Tp value_type;
   typedef _DiffType difference_type;
   typedef value_type& reference;
   typedef typename _NodeTypes::__node_value_type_pointer pointer;
 
   _LIBCPP_HIDE_FROM_ABI __tree_iterator() _NOEXCEPT
 #if _LIBCPP_STD_VER >= 14
       : __ptr_(nullptr)
 #endif
   {
   }
 
   _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __get_np()->__value_; }
   _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(__get_np()->__value_); }
 
   _LIBCPP_HIDE_FROM_ABI __tree_iterator& operator++() {
     __ptr_ = static_cast<__iter_pointer>(
         std::__tree_next_iter<__end_node_pointer>(static_cast<__node_base_pointer>(__ptr_)));
     return *this;
   }
   _LIBCPP_HIDE_FROM_ABI __tree_iterator operator++(int) {
     __tree_iterator __t(*this);
     ++(*this);
     return __t;
   }
 
   _LIBCPP_HIDE_FROM_ABI __tree_iterator& operator--() {
     __ptr_ = static_cast<__iter_pointer>(
         std::__tree_prev_iter<__node_base_pointer>(static_cast<__end_node_pointer>(__ptr_)));
     return *this;
   }
   _LIBCPP_HIDE_FROM_ABI __tree_iterator operator--(int) {
     __tree_iterator __t(*this);
     --(*this);
     return __t;
   }
 
   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __tree_iterator& __x, const __tree_iterator& __y) {
     return __x.__ptr_ == __y.__ptr_;
   }
   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __tree_iterator& __x, const __tree_iterator& __y) {
     return !(__x == __y);
   }
 
 private:
   _LIBCPP_HIDE_FROM_ABI explicit __tree_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
   _LIBCPP_HIDE_FROM_ABI explicit __tree_iterator(__end_node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
   _LIBCPP_HIDE_FROM_ABI __node_pointer __get_np() const { return static_cast<__node_pointer>(__ptr_); }
   template <class, class, class>
   friend class __tree;
   template <class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS __tree_const_iterator;
   template <class>
   friend class _LIBCPP_TEMPLATE_VIS __map_iterator;
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS map;
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS multimap;
   template <class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS set;
   template <class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS multiset;
 };
 
 template <class _Tp, class _NodePtr, class _DiffType>
 class _LIBCPP_TEMPLATE_VIS __tree_const_iterator {
   typedef __tree_node_types<_NodePtr> _NodeTypes;
   typedef typename _NodeTypes::__node_pointer __node_pointer;
   typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
   typedef typename _NodeTypes::__end_node_pointer __end_node_pointer;
   typedef typename _NodeTypes::__iter_pointer __iter_pointer;
   typedef pointer_traits<__node_pointer> __pointer_traits;
 
   __iter_pointer __ptr_;
 
 public:
   typedef bidirectional_iterator_tag iterator_category;
   typedef _Tp value_type;
   typedef _DiffType difference_type;
   typedef const value_type& reference;
   typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator() _NOEXCEPT
 #if _LIBCPP_STD_VER >= 14
       : __ptr_(nullptr)
 #endif
   {
   }
 
 private:
   typedef __tree_iterator<value_type, __node_pointer, difference_type> __non_const_iterator;
 
 public:
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator(__non_const_iterator __p) _NOEXCEPT : __ptr_(__p.__ptr_) {}
 
   _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __get_np()->__value_; }
   _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(__get_np()->__value_); }
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator& operator++() {
     __ptr_ = static_cast<__iter_pointer>(
         std::__tree_next_iter<__end_node_pointer>(static_cast<__node_base_pointer>(__ptr_)));
     return *this;
   }
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator operator++(int) {
     __tree_const_iterator __t(*this);
     ++(*this);
     return __t;
   }
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator& operator--() {
     __ptr_ = static_cast<__iter_pointer>(
         std::__tree_prev_iter<__node_base_pointer>(static_cast<__end_node_pointer>(__ptr_)));
     return *this;
   }
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator operator--(int) {
     __tree_const_iterator __t(*this);
     --(*this);
     return __t;
   }
 
   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __tree_const_iterator& __x, const __tree_const_iterator& __y) {
     return __x.__ptr_ == __y.__ptr_;
   }
   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __tree_const_iterator& __x, const __tree_const_iterator& __y) {
     return !(__x == __y);
   }
 
 private:
   _LIBCPP_HIDE_FROM_ABI explicit __tree_const_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
   _LIBCPP_HIDE_FROM_ABI explicit __tree_const_iterator(__end_node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
   _LIBCPP_HIDE_FROM_ABI __node_pointer __get_np() const { return static_cast<__node_pointer>(__ptr_); }
 
   template <class, class, class>
   friend class __tree;
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS map;
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS multimap;
   template <class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS set;
   template <class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS multiset;
   template <class>
   friend class _LIBCPP_TEMPLATE_VIS __map_const_iterator;
 };
 
 template <class _Tp, class _Compare>
 #ifndef _LIBCPP_CXX03_LANG
 _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Compare const&, _Tp const&, _Tp const&>::value,
                          "the specified comparator type does not provide a viable const call operator")
 #endif
 int __diagnose_non_const_comparator();
 
 template <class _Tp, class _Compare, class _Allocator>
 class __tree {
 public:
   typedef _Tp value_type;
   typedef _Compare value_compare;
   typedef _Allocator allocator_type;
 
 private:
   typedef allocator_traits<allocator_type> __alloc_traits;
   typedef typename __make_tree_node_types<value_type, typename __alloc_traits::void_pointer>::type _NodeTypes;
   typedef typename _NodeTypes::key_type key_type;
 
 public:
   typedef typename _NodeTypes::__node_value_type __node_value_type;
   typedef typename _NodeTypes::__container_value_type __container_value_type;
 
   typedef typename __alloc_traits::pointer pointer;
   typedef typename __alloc_traits::const_pointer const_pointer;
   typedef typename __alloc_traits::size_type size_type;
   typedef typename __alloc_traits::difference_type difference_type;
 
 public:
   typedef typename _NodeTypes::__void_pointer __void_pointer;
 
   typedef typename _NodeTypes::__node_type __node;
   typedef typename _NodeTypes::__node_pointer __node_pointer;
 
   typedef typename _NodeTypes::__node_base_type __node_base;
   typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
 
   typedef typename _NodeTypes::__end_node_type __end_node_t;
   typedef typename _NodeTypes::__end_node_pointer __end_node_ptr;
 
   typedef typename _NodeTypes::__parent_pointer __parent_pointer;
   typedef typename _NodeTypes::__iter_pointer __iter_pointer;
 
   typedef __rebind_alloc<__alloc_traits, __node> __node_allocator;
   typedef allocator_traits<__node_allocator> __node_traits;
 
 private:
   // check for sane allocator pointer rebinding semantics. Rebinding the
   // allocator for a new pointer type should be exactly the same as rebinding
   // the pointer using 'pointer_traits'.
   static_assert(is_same<__node_pointer, typename __node_traits::pointer>::value,
                 "Allocator does not rebind pointers in a sane manner.");
   typedef __rebind_alloc<__node_traits, __node_base> __node_base_allocator;
   typedef allocator_traits<__node_base_allocator> __node_base_traits;
   static_assert(is_same<__node_base_pointer, typename __node_base_traits::pointer>::value,
                 "Allocator does not rebind pointers in a sane manner.");
 
 private:
   __iter_pointer __begin_node_;
   __compressed_pair<__end_node_t, __node_allocator> __pair1_;
   __compressed_pair<size_type, value_compare> __pair3_;
 
 public:
   _LIBCPP_HIDE_FROM_ABI __iter_pointer __end_node() _NOEXCEPT {
     return static_cast<__iter_pointer>(pointer_traits<__end_node_ptr>::pointer_to(__pair1_.first()));
   }
   _LIBCPP_HIDE_FROM_ABI __iter_pointer __end_node() const _NOEXCEPT {
     return static_cast<__iter_pointer>(
         pointer_traits<__end_node_ptr>::pointer_to(const_cast<__end_node_t&>(__pair1_.first())));
   }
   _LIBCPP_HIDE_FROM_ABI __node_allocator& __node_alloc() _NOEXCEPT { return __pair1_.second(); }
 
 private:
   _LIBCPP_HIDE_FROM_ABI const __node_allocator& __node_alloc() const _NOEXCEPT { return __pair1_.second(); }
   _LIBCPP_HIDE_FROM_ABI __iter_pointer& __begin_node() _NOEXCEPT { return __begin_node_; }
   _LIBCPP_HIDE_FROM_ABI const __iter_pointer& __begin_node() const _NOEXCEPT { return __begin_node_; }
 
 public:
   _LIBCPP_HIDE_FROM_ABI allocator_type __alloc() const _NOEXCEPT { return allocator_type(__node_alloc()); }
 
 private:
   _LIBCPP_HIDE_FROM_ABI size_type& size() _NOEXCEPT { return __pair3_.first(); }
 
 public:
   _LIBCPP_HIDE_FROM_ABI const size_type& size() const _NOEXCEPT { return __pair3_.first(); }
   _LIBCPP_HIDE_FROM_ABI value_compare& value_comp() _NOEXCEPT { return __pair3_.second(); }
   _LIBCPP_HIDE_FROM_ABI const value_compare& value_comp() const _NOEXCEPT { return __pair3_.second(); }
 
 public:
   _LIBCPP_HIDE_FROM_ABI __node_pointer __root() const _NOEXCEPT {
     return static_cast<__node_pointer>(__end_node()->__left_);
   }
 
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer* __root_ptr() const _NOEXCEPT {
     return std::addressof(__end_node()->__left_);
   }
 
   typedef __tree_iterator<value_type, __node_pointer, difference_type> iterator;
   typedef __tree_const_iterator<value_type, __node_pointer, difference_type> const_iterator;
 
   _LIBCPP_HIDE_FROM_ABI explicit __tree(const value_compare& __comp) _NOEXCEPT_(
       is_nothrow_default_constructible<__node_allocator>::value&& is_nothrow_copy_constructible<value_compare>::value);
   _LIBCPP_HIDE_FROM_ABI explicit __tree(const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI __tree(const value_compare& __comp, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI __tree(const __tree& __t);
   _LIBCPP_HIDE_FROM_ABI __tree& operator=(const __tree& __t);
   template <class _ForwardIterator>
   _LIBCPP_HIDE_FROM_ABI void __assign_unique(_ForwardIterator __first, _ForwardIterator __last);
   template <class _InputIterator>
   _LIBCPP_HIDE_FROM_ABI void __assign_multi(_InputIterator __first, _InputIterator __last);
   _LIBCPP_HIDE_FROM_ABI __tree(__tree&& __t) _NOEXCEPT_(
       is_nothrow_move_constructible<__node_allocator>::value&& is_nothrow_move_constructible<value_compare>::value);
   _LIBCPP_HIDE_FROM_ABI __tree(__tree&& __t, const allocator_type& __a);
   _LIBCPP_HIDE_FROM_ABI __tree& operator=(__tree&& __t) _NOEXCEPT_(
       __node_traits::propagate_on_container_move_assignment::value&& is_nothrow_move_assignable<value_compare>::value&&
           is_nothrow_move_assignable<__node_allocator>::value);
   _LIBCPP_HIDE_FROM_ABI ~__tree();
 
   _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return iterator(__begin_node()); }
   _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return const_iterator(__begin_node()); }
   _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return iterator(__end_node()); }
   _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return const_iterator(__end_node()); }
 
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
     return std::min<size_type>(__node_traits::max_size(__node_alloc()), numeric_limits<difference_type >::max());
   }
 
   _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT;
 
   _LIBCPP_HIDE_FROM_ABI void swap(__tree& __t)
 #if _LIBCPP_STD_VER <= 11
       _NOEXCEPT_(__is_nothrow_swappable_v<value_compare> &&
                  (!__node_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<__node_allocator>));
 #else
       _NOEXCEPT_(__is_nothrow_swappable_v<value_compare>);
 #endif
 
   template <class _Key, class... _Args>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args&&... __args);
   template <class _Key, class... _Args>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_hint_unique_key_args(const_iterator, _Key const&, _Args&&...);
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_unique_impl(const_iterator __p, _Args&&... __args);
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_multi(_Args&&... __args);
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_Pp&& __x) {
     return __emplace_unique_extract_key(std::forward<_Pp>(__x), __can_extract_key<_Pp, key_type>());
   }
 
   template <class _First,
             class _Second,
             __enable_if_t<__can_extract_map_key<_First, key_type, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_First&& __f, _Second&& __s) {
     return __emplace_unique_key_args(__f, std::forward<_First>(__f), std::forward<_Second>(__s));
   }
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_Args&&... __args) {
     return __emplace_unique_impl(std::forward<_Args>(__args)...);
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
     return __emplace_unique_impl(std::forward<_Pp>(__x));
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
     return __emplace_unique_key_args(__x, std::forward<_Pp>(__x));
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
     return __emplace_unique_key_args(__x.first, std::forward<_Pp>(__x));
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_unique(const_iterator __p, _Pp&& __x) {
     return __emplace_hint_unique_extract_key(__p, std::forward<_Pp>(__x), __can_extract_key<_Pp, key_type>());
   }
 
   template <class _First,
             class _Second,
             __enable_if_t<__can_extract_map_key<_First, key_type, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_unique(const_iterator __p, _First&& __f, _Second&& __s) {
     return __emplace_hint_unique_key_args(__p, __f, std::forward<_First>(__f), std::forward<_Second>(__s)).first;
   }
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_unique(const_iterator __p, _Args&&... __args) {
     return __emplace_hint_unique_impl(__p, std::forward<_Args>(__args)...);
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI iterator
   __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_fail_tag) {
     return __emplace_hint_unique_impl(__p, std::forward<_Pp>(__x));
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI iterator
   __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_self_tag) {
     return __emplace_hint_unique_key_args(__p, __x, std::forward<_Pp>(__x)).first;
   }
 
   template <class _Pp>
   _LIBCPP_HIDE_FROM_ABI iterator
   __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_first_tag) {
     return __emplace_hint_unique_key_args(__p, __x.first, std::forward<_Pp>(__x)).first;
   }
 
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(const __container_value_type& __v) {
     return __emplace_unique_key_args(_NodeTypes::__get_key(__v), __v);
   }
 
   _LIBCPP_HIDE_FROM_ABI iterator __insert_unique(const_iterator __p, const __container_value_type& __v) {
     return __emplace_hint_unique_key_args(__p, _NodeTypes::__get_key(__v), __v).first;
   }
 
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(__container_value_type&& __v) {
     return __emplace_unique_key_args(_NodeTypes::__get_key(__v), std::move(__v));
   }
 
   _LIBCPP_HIDE_FROM_ABI iterator __insert_unique(const_iterator __p, __container_value_type&& __v) {
     return __emplace_hint_unique_key_args(__p, _NodeTypes::__get_key(__v), std::move(__v)).first;
   }
 
   template <class _Vp, __enable_if_t<!is_same<__remove_const_ref_t<_Vp>, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(_Vp&& __v) {
     return __emplace_unique(std::forward<_Vp>(__v));
   }
 
   template <class _Vp, __enable_if_t<!is_same<__remove_const_ref_t<_Vp>, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI iterator __insert_unique(const_iterator __p, _Vp&& __v) {
     return __emplace_hint_unique(__p, std::forward<_Vp>(__v));
   }
 
   _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(__container_value_type&& __v) {
     return __emplace_multi(std::move(__v));
   }
 
   _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(const_iterator __p, __container_value_type&& __v) {
     return __emplace_hint_multi(__p, std::move(__v));
   }
 
   template <class _Vp>
   _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(_Vp&& __v) {
     return __emplace_multi(std::forward<_Vp>(__v));
   }
 
   template <class _Vp>
   _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(const_iterator __p, _Vp&& __v) {
     return __emplace_hint_multi(__p, std::forward<_Vp>(__v));
   }
 
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool>
   __node_assign_unique(const __container_value_type& __v, __node_pointer __dest);
 
   _LIBCPP_HIDE_FROM_ABI iterator __node_insert_multi(__node_pointer __nd);
   _LIBCPP_HIDE_FROM_ABI iterator __node_insert_multi(const_iterator __p, __node_pointer __nd);
 
   _LIBCPP_HIDE_FROM_ABI iterator __remove_node_pointer(__node_pointer) _NOEXCEPT;
 
 #if _LIBCPP_STD_VER >= 17
   template <class _NodeHandle, class _InsertReturnType>
   _LIBCPP_HIDE_FROM_ABI _InsertReturnType __node_handle_insert_unique(_NodeHandle&&);
   template <class _NodeHandle>
   _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_unique(const_iterator, _NodeHandle&&);
   template <class _Tree>
   _LIBCPP_HIDE_FROM_ABI void __node_handle_merge_unique(_Tree& __source);
 
   template <class _NodeHandle>
   _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_multi(_NodeHandle&&);
   template <class _NodeHandle>
   _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_multi(const_iterator, _NodeHandle&&);
   template <class _Tree>
   _LIBCPP_HIDE_FROM_ABI void __node_handle_merge_multi(_Tree& __source);
 
   template <class _NodeHandle>
   _LIBCPP_HIDE_FROM_ABI _NodeHandle __node_handle_extract(key_type const&);
   template <class _NodeHandle>
   _LIBCPP_HIDE_FROM_ABI _NodeHandle __node_handle_extract(const_iterator);
 #endif
 
   _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p);
   _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __f, const_iterator __l);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI size_type __erase_unique(const _Key& __k);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI size_type __erase_multi(const _Key& __k);
 
   _LIBCPP_HIDE_FROM_ABI void
   __insert_node_at(__parent_pointer __parent, __node_base_pointer& __child, __node_base_pointer __new_node) _NOEXCEPT;
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI iterator find(const _Key& __v);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI const_iterator find(const _Key& __v) const;
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI size_type __count_unique(const _Key& __k) const;
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI size_type __count_multi(const _Key& __k) const;
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI iterator lower_bound(const _Key& __v) {
     return __lower_bound(__v, __root(), __end_node());
   }
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI iterator __lower_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const _Key& __v) const {
     return __lower_bound(__v, __root(), __end_node());
   }
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI const_iterator
   __lower_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result) const;
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI iterator upper_bound(const _Key& __v) {
     return __upper_bound(__v, __root(), __end_node());
   }
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI iterator __upper_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const _Key& __v) const {
     return __upper_bound(__v, __root(), __end_node());
   }
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI const_iterator
   __upper_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result) const;
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> __equal_range_unique(const _Key& __k);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> __equal_range_unique(const _Key& __k) const;
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> __equal_range_multi(const _Key& __k);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> __equal_range_multi(const _Key& __k) const;
 
   typedef __tree_node_destructor<__node_allocator> _Dp;
   typedef unique_ptr<__node, _Dp> __node_holder;
 
   _LIBCPP_HIDE_FROM_ABI __node_holder remove(const_iterator __p) _NOEXCEPT;
 
 private:
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer& __find_leaf_low(__parent_pointer& __parent, const key_type& __v);
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer& __find_leaf_high(__parent_pointer& __parent, const key_type& __v);
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer&
   __find_leaf(const_iterator __hint, __parent_pointer& __parent, const key_type& __v);
   // FIXME: Make this function const qualified. Unfortunately doing so
   // breaks existing code which uses non-const callable comparators.
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer& __find_equal(__parent_pointer& __parent, const _Key& __v);
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer& __find_equal(__parent_pointer& __parent, const _Key& __v) const {
     return const_cast<__tree*>(this)->__find_equal(__parent, __v);
   }
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI __node_base_pointer&
   __find_equal(const_iterator __hint, __parent_pointer& __parent, __node_base_pointer& __dummy, const _Key& __v);
 
   template <class... _Args>
   _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node(_Args&&... __args);
 
   // TODO: Make this _LIBCPP_HIDE_FROM_ABI
   _LIBCPP_HIDDEN void destroy(__node_pointer __nd) _NOEXCEPT;
 
   _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __tree& __t) {
     __copy_assign_alloc(__t, integral_constant<bool, __node_traits::propagate_on_container_copy_assignment::value>());
   }
 
   _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __tree& __t, true_type) {
     if (__node_alloc() != __t.__node_alloc())
       clear();
     __node_alloc() = __t.__node_alloc();
   }
   _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __tree&, false_type) {}
 
   _LIBCPP_HIDE_FROM_ABI void __move_assign(__tree& __t, false_type);
   _LIBCPP_HIDE_FROM_ABI void __move_assign(__tree& __t, true_type) _NOEXCEPT_(
       is_nothrow_move_assignable<value_compare>::value&& is_nothrow_move_assignable<__node_allocator>::value);
 
   _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__tree& __t)
       _NOEXCEPT_(!__node_traits::propagate_on_container_move_assignment::value ||
                  is_nothrow_move_assignable<__node_allocator>::value) {
     __move_assign_alloc(__t, integral_constant<bool, __node_traits::propagate_on_container_move_assignment::value>());
   }
 
   _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__tree& __t, true_type)
       _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value) {
     __node_alloc() = std::move(__t.__node_alloc());
   }
   _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__tree&, false_type) _NOEXCEPT {}
 
   struct _DetachedTreeCache {
     _LIBCPP_HIDE_FROM_ABI explicit _DetachedTreeCache(__tree* __t) _NOEXCEPT
         : __t_(__t),
           __cache_root_(__detach_from_tree(__t)) {
       __advance();
     }
 
     _LIBCPP_HIDE_FROM_ABI __node_pointer __get() const _NOEXCEPT { return __cache_elem_; }
 
     _LIBCPP_HIDE_FROM_ABI void __advance() _NOEXCEPT {
       __cache_elem_ = __cache_root_;
       if (__cache_root_) {
         __cache_root_ = __detach_next(__cache_root_);
       }
     }
 
     _LIBCPP_HIDE_FROM_ABI ~_DetachedTreeCache() {
       __t_->destroy(__cache_elem_);
       if (__cache_root_) {
         while (__cache_root_->__parent_ != nullptr)
           __cache_root_ = static_cast<__node_pointer>(__cache_root_->__parent_);
         __t_->destroy(__cache_root_);
       }
     }
 
     _DetachedTreeCache(_DetachedTreeCache const&)            = delete;
     _DetachedTreeCache& operator=(_DetachedTreeCache const&) = delete;
 
   private:
     _LIBCPP_HIDE_FROM_ABI static __node_pointer __detach_from_tree(__tree* __t) _NOEXCEPT;
     _LIBCPP_HIDE_FROM_ABI static __node_pointer __detach_next(__node_pointer) _NOEXCEPT;
 
     __tree* __t_;
     __node_pointer __cache_root_;
     __node_pointer __cache_elem_;
   };
 
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS map;
   template <class, class, class, class>
   friend class _LIBCPP_TEMPLATE_VIS multimap;
 };
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(const value_compare& __comp) _NOEXCEPT_(
     is_nothrow_default_constructible<__node_allocator>::value&& is_nothrow_copy_constructible<value_compare>::value)
     : __pair3_(0, __comp) {
   __begin_node() = __end_node();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(const allocator_type& __a)
     : __begin_node_(__iter_pointer()),
       __pair1_(__default_init_tag(), __node_allocator(__a)),
       __pair3_(0, __default_init_tag()) {
   __begin_node() = __end_node();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(const value_compare& __comp, const allocator_type& __a)
     : __begin_node_(__iter_pointer()), __pair1_(__default_init_tag(), __node_allocator(__a)), __pair3_(0, __comp) {
   __begin_node() = __end_node();
 }
 
 // Precondition:  size() != 0
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_pointer
 __tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_from_tree(__tree* __t) _NOEXCEPT {
   __node_pointer __cache                = static_cast<__node_pointer>(__t->__begin_node());
   __t->__begin_node()                   = __t->__end_node();
   __t->__end_node()->__left_->__parent_ = nullptr;
   __t->__end_node()->__left_            = nullptr;
   __t->size()                           = 0;
   // __cache->__left_ == nullptr
   if (__cache->__right_ != nullptr)
     __cache = static_cast<__node_pointer>(__cache->__right_);
   // __cache->__left_ == nullptr
   // __cache->__right_ == nullptr
   return __cache;
 }
 
 // Precondition:  __cache != nullptr
 //    __cache->left_ == nullptr
 //    __cache->right_ == nullptr
 //    This is no longer a red-black tree
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_pointer
 __tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_next(__node_pointer __cache) _NOEXCEPT {
   if (__cache->__parent_ == nullptr)
     return nullptr;
   if (std::__tree_is_left_child(static_cast<__node_base_pointer>(__cache))) {
     __cache->__parent_->__left_ = nullptr;
     __cache                     = static_cast<__node_pointer>(__cache->__parent_);
     if (__cache->__right_ == nullptr)
       return __cache;
     return static_cast<__node_pointer>(std::__tree_leaf(__cache->__right_));
   }
   // __cache is right child
   __cache->__parent_unsafe()->__right_ = nullptr;
   __cache                              = static_cast<__node_pointer>(__cache->__parent_);
   if (__cache->__left_ == nullptr)
     return __cache;
   return static_cast<__node_pointer>(std::__tree_leaf(__cache->__left_));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>& __tree<_Tp, _Compare, _Allocator>::operator=(const __tree& __t) {
   if (this != std::addressof(__t)) {
     value_comp() = __t.value_comp();
     __copy_assign_alloc(__t);
     __assign_multi(__t.begin(), __t.end());
   }
   return *this;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _ForwardIterator>
 void __tree<_Tp, _Compare, _Allocator>::__assign_unique(_ForwardIterator __first, _ForwardIterator __last) {
   typedef iterator_traits<_ForwardIterator> _ITraits;
   typedef typename _ITraits::value_type _ItValueType;
   static_assert(is_same<_ItValueType, __container_value_type>::value,
                 "__assign_unique may only be called with the containers value type");
   static_assert(
       __has_forward_iterator_category<_ForwardIterator>::value, "__assign_unique requires a forward iterator");
   if (size() != 0) {
     _DetachedTreeCache __cache(this);
     for (; __cache.__get() != nullptr && __first != __last; ++__first) {
       if (__node_assign_unique(*__first, __cache.__get()).second)
         __cache.__advance();
     }
   }
   for (; __first != __last; ++__first)
     __insert_unique(*__first);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _InputIterator>
 void __tree<_Tp, _Compare, _Allocator>::__assign_multi(_InputIterator __first, _InputIterator __last) {
   typedef iterator_traits<_InputIterator> _ITraits;
   typedef typename _ITraits::value_type _ItValueType;
   static_assert(
       (is_same<_ItValueType, __container_value_type>::value || is_same<_ItValueType, __node_value_type>::value),
       "__assign_multi may only be called with the containers value type"
       " or the nodes value type");
   if (size() != 0) {
     _DetachedTreeCache __cache(this);
     for (; __cache.__get() && __first != __last; ++__first) {
       __cache.__get()->__value_ = *__first;
       __node_insert_multi(__cache.__get());
       __cache.__advance();
     }
   }
   for (; __first != __last; ++__first)
     __insert_multi(_NodeTypes::__get_value(*__first));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(const __tree& __t)
     : __begin_node_(__iter_pointer()),
       __pair1_(__default_init_tag(), __node_traits::select_on_container_copy_construction(__t.__node_alloc())),
       __pair3_(0, __t.value_comp()) {
   __begin_node() = __end_node();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(__tree&& __t) _NOEXCEPT_(
     is_nothrow_move_constructible<__node_allocator>::value&& is_nothrow_move_constructible<value_compare>::value)
     : __begin_node_(std::move(__t.__begin_node_)),
       __pair1_(std::move(__t.__pair1_)),
       __pair3_(std::move(__t.__pair3_)) {
   if (size() == 0)
     __begin_node() = __end_node();
   else {
     __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
     __t.__begin_node()               = __t.__end_node();
     __t.__end_node()->__left_        = nullptr;
     __t.size()                       = 0;
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(__tree&& __t, const allocator_type& __a)
     : __pair1_(__default_init_tag(), __node_allocator(__a)), __pair3_(0, std::move(__t.value_comp())) {
   if (__a == __t.__alloc()) {
     if (__t.size() == 0)
       __begin_node() = __end_node();
     else {
       __begin_node()                   = __t.__begin_node();
       __end_node()->__left_            = __t.__end_node()->__left_;
       __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
       size()                           = __t.size();
       __t.__begin_node()               = __t.__end_node();
       __t.__end_node()->__left_        = nullptr;
       __t.size()                       = 0;
     }
   } else {
     __begin_node() = __end_node();
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::__move_assign(__tree& __t, true_type)
     _NOEXCEPT_(is_nothrow_move_assignable<value_compare>::value&& is_nothrow_move_assignable<__node_allocator>::value) {
   destroy(static_cast<__node_pointer>(__end_node()->__left_));
   __begin_node_    = __t.__begin_node_;
   __pair1_.first() = __t.__pair1_.first();
   __move_assign_alloc(__t);
   __pair3_ = std::move(__t.__pair3_);
   if (size() == 0)
     __begin_node() = __end_node();
   else {
     __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
     __t.__begin_node()               = __t.__end_node();
     __t.__end_node()->__left_        = nullptr;
     __t.size()                       = 0;
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::__move_assign(__tree& __t, false_type) {
   if (__node_alloc() == __t.__node_alloc())
     __move_assign(__t, true_type());
   else {
     value_comp()       = std::move(__t.value_comp());
     const_iterator __e = end();
     if (size() != 0) {
       _DetachedTreeCache __cache(this);
       while (__cache.__get() != nullptr && __t.size() != 0) {
         __cache.__get()->__value_ = std::move(__t.remove(__t.begin())->__value_);
         __node_insert_multi(__cache.__get());
         __cache.__advance();
       }
     }
     while (__t.size() != 0)
       __insert_multi(__e, _NodeTypes::__move(__t.remove(__t.begin())->__value_));
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>& __tree<_Tp, _Compare, _Allocator>::operator=(__tree&& __t) _NOEXCEPT_(
     __node_traits::propagate_on_container_move_assignment::value&& is_nothrow_move_assignable<value_compare>::value&&
         is_nothrow_move_assignable<__node_allocator>::value)
 
 {
   __move_assign(__t, integral_constant<bool, __node_traits::propagate_on_container_move_assignment::value>());
   return *this;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::~__tree() {
   static_assert(is_copy_constructible<value_compare>::value, "Comparator must be copy-constructible.");
   destroy(__root());
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::destroy(__node_pointer __nd) _NOEXCEPT {
   if (__nd != nullptr) {
     destroy(static_cast<__node_pointer>(__nd->__left_));
     destroy(static_cast<__node_pointer>(__nd->__right_));
     __node_allocator& __na = __node_alloc();
     __node_traits::destroy(__na, _NodeTypes::__get_ptr(__nd->__value_));
     __node_traits::deallocate(__na, __nd, 1);
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::swap(__tree& __t)
 #if _LIBCPP_STD_VER <= 11
     _NOEXCEPT_(__is_nothrow_swappable_v<value_compare> &&
                (!__node_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<__node_allocator>))
 #else
     _NOEXCEPT_(__is_nothrow_swappable_v<value_compare>)
 #endif
 {
   using std::swap;
   swap(__begin_node_, __t.__begin_node_);
   swap(__pair1_.first(), __t.__pair1_.first());
   std::__swap_allocator(__node_alloc(), __t.__node_alloc());
   __pair3_.swap(__t.__pair3_);
   if (size() == 0)
     __begin_node() = __end_node();
   else
     __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
   if (__t.size() == 0)
     __t.__begin_node() = __t.__end_node();
   else
     __t.__end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__t.__end_node());
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::clear() _NOEXCEPT {
   destroy(__root());
   size()                = 0;
   __begin_node()        = __end_node();
   __end_node()->__left_ = nullptr;
 }
 
 // Find lower_bound place to insert
 // Set __parent to parent of null leaf
 // Return reference to null leaf
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
 __tree<_Tp, _Compare, _Allocator>::__find_leaf_low(__parent_pointer& __parent, const key_type& __v) {
   __node_pointer __nd = __root();
   if (__nd != nullptr) {
     while (true) {
       if (value_comp()(__nd->__value_, __v)) {
         if (__nd->__right_ != nullptr)
           __nd = static_cast<__node_pointer>(__nd->__right_);
         else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __nd->__right_;
         }
       } else {
         if (__nd->__left_ != nullptr)
           __nd = static_cast<__node_pointer>(__nd->__left_);
         else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __parent->__left_;
         }
       }
     }
   }
   __parent = static_cast<__parent_pointer>(__end_node());
   return __parent->__left_;
 }
 
 // Find upper_bound place to insert
 // Set __parent to parent of null leaf
 // Return reference to null leaf
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
 __tree<_Tp, _Compare, _Allocator>::__find_leaf_high(__parent_pointer& __parent, const key_type& __v) {
   __node_pointer __nd = __root();
   if (__nd != nullptr) {
     while (true) {
       if (value_comp()(__v, __nd->__value_)) {
         if (__nd->__left_ != nullptr)
           __nd = static_cast<__node_pointer>(__nd->__left_);
         else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __parent->__left_;
         }
       } else {
         if (__nd->__right_ != nullptr)
           __nd = static_cast<__node_pointer>(__nd->__right_);
         else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __nd->__right_;
         }
       }
     }
   }
   __parent = static_cast<__parent_pointer>(__end_node());
   return __parent->__left_;
 }
 
 // Find leaf place to insert closest to __hint
 // First check prior to __hint.
 // Next check after __hint.
 // Next do O(log N) search.
 // Set __parent to parent of null leaf
 // Return reference to null leaf
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
 __tree<_Tp, _Compare, _Allocator>::__find_leaf(const_iterator __hint, __parent_pointer& __parent, const key_type& __v) {
   if (__hint == end() || !value_comp()(*__hint, __v)) // check before
   {
     // __v <= *__hint
     const_iterator __prior = __hint;
     if (__prior == begin() || !value_comp()(__v, *--__prior)) {
       // *prev(__hint) <= __v <= *__hint
       if (__hint.__ptr_->__left_ == nullptr) {
         __parent = static_cast<__parent_pointer>(__hint.__ptr_);
         return __parent->__left_;
       } else {
         __parent = static_cast<__parent_pointer>(__prior.__ptr_);
         return static_cast<__node_base_pointer>(__prior.__ptr_)->__right_;
       }
     }
     // __v < *prev(__hint)
     return __find_leaf_high(__parent, __v);
   }
   // else __v > *__hint
   return __find_leaf_low(__parent, __v);
 }
 
 // Find place to insert if __v doesn't exist
 // Set __parent to parent of null leaf
 // Return reference to null leaf
 // If __v exists, set parent to node of __v and return reference to node of __v
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
 __tree<_Tp, _Compare, _Allocator>::__find_equal(__parent_pointer& __parent, const _Key& __v) {
   __node_pointer __nd           = __root();
   __node_base_pointer* __nd_ptr = __root_ptr();
   if (__nd != nullptr) {
     while (true) {
       if (value_comp()(__v, __nd->__value_)) {
         if (__nd->__left_ != nullptr) {
           __nd_ptr = std::addressof(__nd->__left_);
           __nd     = static_cast<__node_pointer>(__nd->__left_);
         } else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __parent->__left_;
         }
       } else if (value_comp()(__nd->__value_, __v)) {
         if (__nd->__right_ != nullptr) {
           __nd_ptr = std::addressof(__nd->__right_);
           __nd     = static_cast<__node_pointer>(__nd->__right_);
         } else {
           __parent = static_cast<__parent_pointer>(__nd);
           return __nd->__right_;
         }
       } else {
         __parent = static_cast<__parent_pointer>(__nd);
         return *__nd_ptr;
       }
     }
   }
   __parent = static_cast<__parent_pointer>(__end_node());
   return __parent->__left_;
 }
 
 // Find place to insert if __v doesn't exist
 // First check prior to __hint.
 // Next check after __hint.
 // Next do O(log N) search.
 // Set __parent to parent of null leaf
 // Return reference to null leaf
 // If __v exists, set parent to node of __v and return reference to node of __v
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer& __tree<_Tp, _Compare, _Allocator>::__find_equal(
     const_iterator __hint, __parent_pointer& __parent, __node_base_pointer& __dummy, const _Key& __v) {
   if (__hint == end() || value_comp()(__v, *__hint)) // check before
   {
     // __v < *__hint
     const_iterator __prior = __hint;
     if (__prior == begin() || value_comp()(*--__prior, __v)) {
       // *prev(__hint) < __v < *__hint
       if (__hint.__ptr_->__left_ == nullptr) {
         __parent = static_cast<__parent_pointer>(__hint.__ptr_);
         return __parent->__left_;
       } else {
         __parent = static_cast<__parent_pointer>(__prior.__ptr_);
         return static_cast<__node_base_pointer>(__prior.__ptr_)->__right_;
       }
     }
     // __v <= *prev(__hint)
     return __find_equal(__parent, __v);
   } else if (value_comp()(*__hint, __v)) // check after
   {
     // *__hint < __v
     const_iterator __next = std::next(__hint);
     if (__next == end() || value_comp()(__v, *__next)) {
       // *__hint < __v < *std::next(__hint)
       if (__hint.__get_np()->__right_ == nullptr) {
         __parent = static_cast<__parent_pointer>(__hint.__ptr_);
         return static_cast<__node_base_pointer>(__hint.__ptr_)->__right_;
       } else {
         __parent = static_cast<__parent_pointer>(__next.__ptr_);
         return __parent->__left_;
       }
     }
     // *next(__hint) <= __v
     return __find_equal(__parent, __v);
   }
   // else __v == *__hint
   __parent = static_cast<__parent_pointer>(__hint.__ptr_);
   __dummy  = static_cast<__node_base_pointer>(__hint.__ptr_);
   return __dummy;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::__insert_node_at(
     __parent_pointer __parent, __node_base_pointer& __child, __node_base_pointer __new_node) _NOEXCEPT {
   __new_node->__left_   = nullptr;
   __new_node->__right_  = nullptr;
   __new_node->__parent_ = __parent;
   // __new_node->__is_black_ is initialized in __tree_balance_after_insert
   __child = __new_node;
   if (__begin_node()->__left_ != nullptr)
     __begin_node() = static_cast<__iter_pointer>(__begin_node()->__left_);
   std::__tree_balance_after_insert(__end_node()->__left_, __child);
   ++size();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key, class... _Args>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args) {
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_equal(__parent, __k);
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   bool __inserted              = false;
   if (__child == nullptr) {
     __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
     __r        = __h.release();
     __inserted = true;
   }
   return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key, class... _Args>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
     const_iterator __p, _Key const& __k, _Args&&... __args) {
   __parent_pointer __parent;
   __node_base_pointer __dummy;
   __node_base_pointer& __child = __find_equal(__p, __parent, __dummy, __k);
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   bool __inserted              = false;
   if (__child == nullptr) {
     __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
     __r        = __h.release();
     __inserted = true;
   }
   return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class... _Args>
 typename __tree<_Tp, _Compare, _Allocator>::__node_holder
 __tree<_Tp, _Compare, _Allocator>::__construct_node(_Args&&... __args) {
   static_assert(!__is_tree_value_type<_Args...>::value, "Cannot construct from __value_type");
   __node_allocator& __na = __node_alloc();
   __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
   __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), std::forward<_Args>(__args)...);
   __h.get_deleter().__value_constructed = true;
   return __h;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class... _Args>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__emplace_unique_impl(_Args&&... __args) {
   __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_equal(__parent, __h->__value_);
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   bool __inserted              = false;
   if (__child == nullptr) {
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
     __r        = __h.release();
     __inserted = true;
   }
   return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class... _Args>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_impl(const_iterator __p, _Args&&... __args) {
   __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
   __parent_pointer __parent;
   __node_base_pointer __dummy;
   __node_base_pointer& __child = __find_equal(__p, __parent, __dummy, __h->__value_);
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   if (__child == nullptr) {
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
     __r = __h.release();
   }
   return iterator(__r);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class... _Args>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__emplace_multi(_Args&&... __args) {
   __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__h->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
   return iterator(static_cast<__node_pointer>(__h.release()));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class... _Args>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__emplace_hint_multi(const_iterator __p, _Args&&... __args) {
   __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf(__p, __parent, _NodeTypes::__get_key(__h->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
   return iterator(static_cast<__node_pointer>(__h.release()));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__node_assign_unique(const __container_value_type& __v, __node_pointer __nd) {
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_equal(__parent, _NodeTypes::__get_key(__v));
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   bool __inserted              = false;
   if (__child == nullptr) {
     __nd->__value_ = __v;
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
     __r        = __nd;
     __inserted = true;
   }
   return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__node_insert_multi(__node_pointer __nd) {
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__nd->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
   return iterator(__nd);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__node_insert_multi(const_iterator __p, __node_pointer __nd) {
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf(__p, __parent, _NodeTypes::__get_key(__nd->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
   return iterator(__nd);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__remove_node_pointer(__node_pointer __ptr) _NOEXCEPT {
   iterator __r(__ptr);
   ++__r;
   if (__begin_node() == __ptr)
     __begin_node() = __r.__ptr_;
   --size();
   std::__tree_remove(__end_node()->__left_, static_cast<__node_base_pointer>(__ptr));
   return __r;
 }
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle, class _InsertReturnType>
 _LIBCPP_HIDE_FROM_ABI _InsertReturnType
 __tree<_Tp, _Compare, _Allocator>::__node_handle_insert_unique(_NodeHandle&& __nh) {
   if (__nh.empty())
     return _InsertReturnType{end(), false, _NodeHandle()};
 
   __node_pointer __ptr = __nh.__ptr_;
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_equal(__parent, __ptr->__value_);
   if (__child != nullptr)
     return _InsertReturnType{iterator(static_cast<__node_pointer>(__child)), false, std::move(__nh)};
 
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
   __nh.__release_ptr();
   return _InsertReturnType{iterator(__ptr), true, _NodeHandle()};
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle>
 _LIBCPP_HIDE_FROM_ABI typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__node_handle_insert_unique(const_iterator __hint, _NodeHandle&& __nh) {
   if (__nh.empty())
     return end();
 
   __node_pointer __ptr = __nh.__ptr_;
   __parent_pointer __parent;
   __node_base_pointer __dummy;
   __node_base_pointer& __child = __find_equal(__hint, __parent, __dummy, __ptr->__value_);
   __node_pointer __r           = static_cast<__node_pointer>(__child);
   if (__child == nullptr) {
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
     __r = __ptr;
     __nh.__release_ptr();
   }
   return iterator(__r);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle>
 _LIBCPP_HIDE_FROM_ABI _NodeHandle __tree<_Tp, _Compare, _Allocator>::__node_handle_extract(key_type const& __key) {
   iterator __it = find(__key);
   if (__it == end())
     return _NodeHandle();
   return __node_handle_extract<_NodeHandle>(__it);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle>
 _LIBCPP_HIDE_FROM_ABI _NodeHandle __tree<_Tp, _Compare, _Allocator>::__node_handle_extract(const_iterator __p) {
   __node_pointer __np = __p.__get_np();
   __remove_node_pointer(__np);
   return _NodeHandle(__np, __alloc());
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Tree>
 _LIBCPP_HIDE_FROM_ABI void __tree<_Tp, _Compare, _Allocator>::__node_handle_merge_unique(_Tree& __source) {
   static_assert(is_same<typename _Tree::__node_pointer, __node_pointer>::value, "");
 
   for (typename _Tree::iterator __i = __source.begin(); __i != __source.end();) {
     __node_pointer __src_ptr = __i.__get_np();
     __parent_pointer __parent;
     __node_base_pointer& __child = __find_equal(__parent, _NodeTypes::__get_key(__src_ptr->__value_));
     ++__i;
     if (__child != nullptr)
       continue;
     __source.__remove_node_pointer(__src_ptr);
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__src_ptr));
   }
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle>
 _LIBCPP_HIDE_FROM_ABI typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__node_handle_insert_multi(_NodeHandle&& __nh) {
   if (__nh.empty())
     return end();
   __node_pointer __ptr = __nh.__ptr_;
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__ptr->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
   __nh.__release_ptr();
   return iterator(__ptr);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _NodeHandle>
 _LIBCPP_HIDE_FROM_ABI typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh) {
   if (__nh.empty())
     return end();
 
   __node_pointer __ptr = __nh.__ptr_;
   __parent_pointer __parent;
   __node_base_pointer& __child = __find_leaf(__hint, __parent, _NodeTypes::__get_key(__ptr->__value_));
   __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
   __nh.__release_ptr();
   return iterator(__ptr);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Tree>
 _LIBCPP_HIDE_FROM_ABI void __tree<_Tp, _Compare, _Allocator>::__node_handle_merge_multi(_Tree& __source) {
   static_assert(is_same<typename _Tree::__node_pointer, __node_pointer>::value, "");
 
   for (typename _Tree::iterator __i = __source.begin(); __i != __source.end();) {
     __node_pointer __src_ptr = __i.__get_np();
     __parent_pointer __parent;
     __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__src_ptr->__value_));
     ++__i;
     __source.__remove_node_pointer(__src_ptr);
     __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__src_ptr));
   }
 }
 
 #endif // _LIBCPP_STD_VER >= 17
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::iterator __tree<_Tp, _Compare, _Allocator>::erase(const_iterator __p) {
   __node_pointer __np    = __p.__get_np();
   iterator __r           = __remove_node_pointer(__np);
   __node_allocator& __na = __node_alloc();
   __node_traits::destroy(__na, _NodeTypes::__get_ptr(const_cast<__node_value_type&>(*__p)));
   __node_traits::deallocate(__na, __np, 1);
   return __r;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::erase(const_iterator __f, const_iterator __l) {
   while (__f != __l)
     __f = erase(__f);
   return iterator(__l.__ptr_);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::size_type
 __tree<_Tp, _Compare, _Allocator>::__erase_unique(const _Key& __k) {
   iterator __i = find(__k);
   if (__i == end())
     return 0;
   erase(__i);
   return 1;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::size_type
 __tree<_Tp, _Compare, _Allocator>::__erase_multi(const _Key& __k) {
   pair<iterator, iterator> __p = __equal_range_multi(__k);
   size_type __r                = 0;
   for (; __p.first != __p.second; ++__r)
     __p.first = erase(__p.first);
   return __r;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::iterator __tree<_Tp, _Compare, _Allocator>::find(const _Key& __v) {
   iterator __p = __lower_bound(__v, __root(), __end_node());
   if (__p != end() && !value_comp()(__v, *__p))
     return __p;
   return end();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::const_iterator
 __tree<_Tp, _Compare, _Allocator>::find(const _Key& __v) const {
   const_iterator __p = __lower_bound(__v, __root(), __end_node());
   if (__p != end() && !value_comp()(__v, *__p))
     return __p;
   return end();
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::size_type
 __tree<_Tp, _Compare, _Allocator>::__count_unique(const _Key& __k) const {
   __node_pointer __rt = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __rt = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return 1;
   }
   return 0;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::size_type
 __tree<_Tp, _Compare, _Allocator>::__count_multi(const _Key& __k) const {
   __iter_pointer __result = __end_node();
   __node_pointer __rt     = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __result = static_cast<__iter_pointer>(__rt);
       __rt     = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return std::distance(
           __lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
           __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result));
   }
   return 0;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__lower_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result) {
   while (__root != nullptr) {
     if (!value_comp()(__root->__value_, __v)) {
       __result = static_cast<__iter_pointer>(__root);
       __root   = static_cast<__node_pointer>(__root->__left_);
     } else
       __root = static_cast<__node_pointer>(__root->__right_);
   }
   return iterator(__result);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::const_iterator __tree<_Tp, _Compare, _Allocator>::__lower_bound(
     const _Key& __v, __node_pointer __root, __iter_pointer __result) const {
   while (__root != nullptr) {
     if (!value_comp()(__root->__value_, __v)) {
       __result = static_cast<__iter_pointer>(__root);
       __root   = static_cast<__node_pointer>(__root->__left_);
     } else
       __root = static_cast<__node_pointer>(__root->__right_);
   }
   return const_iterator(__result);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::iterator
 __tree<_Tp, _Compare, _Allocator>::__upper_bound(const _Key& __v, __node_pointer __root, __iter_pointer __result) {
   while (__root != nullptr) {
     if (value_comp()(__v, __root->__value_)) {
       __result = static_cast<__iter_pointer>(__root);
       __root   = static_cast<__node_pointer>(__root->__left_);
     } else
       __root = static_cast<__node_pointer>(__root->__right_);
   }
   return iterator(__result);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 typename __tree<_Tp, _Compare, _Allocator>::const_iterator __tree<_Tp, _Compare, _Allocator>::__upper_bound(
     const _Key& __v, __node_pointer __root, __iter_pointer __result) const {
   while (__root != nullptr) {
     if (value_comp()(__v, __root->__value_)) {
       __result = static_cast<__iter_pointer>(__root);
       __root   = static_cast<__node_pointer>(__root->__left_);
     } else
       __root = static_cast<__node_pointer>(__root->__right_);
   }
   return const_iterator(__result);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, typename __tree<_Tp, _Compare, _Allocator>::iterator>
 __tree<_Tp, _Compare, _Allocator>::__equal_range_unique(const _Key& __k) {
   typedef pair<iterator, iterator> _Pp;
   __iter_pointer __result = __end_node();
   __node_pointer __rt     = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __result = static_cast<__iter_pointer>(__rt);
       __rt     = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return _Pp(iterator(__rt),
                  iterator(__rt->__right_ != nullptr ? static_cast<__iter_pointer>(std::__tree_min(__rt->__right_))
                                                     : __result));
   }
   return _Pp(iterator(__result), iterator(__result));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 pair<typename __tree<_Tp, _Compare, _Allocator>::const_iterator,
      typename __tree<_Tp, _Compare, _Allocator>::const_iterator>
 __tree<_Tp, _Compare, _Allocator>::__equal_range_unique(const _Key& __k) const {
   typedef pair<const_iterator, const_iterator> _Pp;
   __iter_pointer __result = __end_node();
   __node_pointer __rt     = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __result = static_cast<__iter_pointer>(__rt);
       __rt     = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return _Pp(
           const_iterator(__rt),
           const_iterator(
               __rt->__right_ != nullptr ? static_cast<__iter_pointer>(std::__tree_min(__rt->__right_)) : __result));
   }
   return _Pp(const_iterator(__result), const_iterator(__result));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, typename __tree<_Tp, _Compare, _Allocator>::iterator>
 __tree<_Tp, _Compare, _Allocator>::__equal_range_multi(const _Key& __k) {
   typedef pair<iterator, iterator> _Pp;
   __iter_pointer __result = __end_node();
   __node_pointer __rt     = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __result = static_cast<__iter_pointer>(__rt);
       __rt     = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return _Pp(__lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
                  __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result));
   }
   return _Pp(iterator(__result), iterator(__result));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key>
 pair<typename __tree<_Tp, _Compare, _Allocator>::const_iterator,
      typename __tree<_Tp, _Compare, _Allocator>::const_iterator>
 __tree<_Tp, _Compare, _Allocator>::__equal_range_multi(const _Key& __k) const {
   typedef pair<const_iterator, const_iterator> _Pp;
   __iter_pointer __result = __end_node();
   __node_pointer __rt     = __root();
   while (__rt != nullptr) {
     if (value_comp()(__k, __rt->__value_)) {
       __result = static_cast<__iter_pointer>(__rt);
       __rt     = static_cast<__node_pointer>(__rt->__left_);
     } else if (value_comp()(__rt->__value_, __k))
       __rt = static_cast<__node_pointer>(__rt->__right_);
     else
       return _Pp(__lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
                  __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result));
   }
   return _Pp(const_iterator(__result), const_iterator(__result));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 typename __tree<_Tp, _Compare, _Allocator>::__node_holder
 __tree<_Tp, _Compare, _Allocator>::remove(const_iterator __p) _NOEXCEPT {
   __node_pointer __np = __p.__get_np();
   if (__begin_node() == __p.__ptr_) {
     if (__np->__right_ != nullptr)
       __begin_node() = static_cast<__iter_pointer>(__np->__right_);
     else
       __begin_node() = static_cast<__iter_pointer>(__np->__parent_);
   }
   --size();
   std::__tree_remove(__end_node()->__left_, static_cast<__node_base_pointer>(__np));
   return __node_holder(__np, _Dp(__node_alloc(), true));
 }
 
 template <class _Tp, class _Compare, class _Allocator>
 inline _LIBCPP_HIDE_FROM_ABI void swap(__tree<_Tp, _Compare, _Allocator>& __x, __tree<_Tp, _Compare, _Allocator>& __y)
     _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
   __x.swap(__y);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP___CXX03___TREE

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