封装红黑树实现mymap和myset

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发布于 2024-12-24 09:55:07

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1. 源码及框架分析

SGI-STL30版本源代码，map和set的源代码在map/set/stl_map.h/stl_set.h/stl_tree.h等⼏个头⽂件中。

map和set的实现结构框架核⼼部分截取出来如下：

// set
#ifndef __SGI_STL_INTERNAL_TREE_H
#include <stl_tree.h>
#endif
#include <stl_set.h>
#include <stl_multiset.h>
// map
#ifndef __SGI_STL_INTERNAL_TREE_H
#include <stl_tree.h>
#endif
#include <stl_map.h>
#include <stl_multimap.h>
// stl_set.h
template <class Key, class Compare = less<Key>, class Alloc = alloc>
class set {
public:
	// typedefs:
	typedef Key key_type;
	typedef Key value_type;
private:
	typedef rb_tree<key_type, value_type,
		identity<value_type>, key_compare, Alloc> rep_type;
	rep_type t; // red-black tree representing set
};
// stl_map.h
template <class Key, class T, class Compare = less<Key>, class Alloc = alloc>
class map {
public:
	// typedefs:
	typedef Key key_type;
	typedef T mapped_type;
	typedef pair<const Key, T> value_type;
private:
	typedef rb_tree<key_type, value_type,
		select1st<value_type>, key_compare, Alloc> rep_type;
	rep_type t; // red-black tree representing map
};
// stl_tree.h
struct __rb_tree_node_base
{
	typedef __rb_tree_color_type color_type;
	typedef __rb_tree_node_base* base_ptr;
	color_type color;
	base_ptr parent;
	base_ptr left;
	base_ptr right;
};
// stl_tree.h
template <class Key, class Value, class KeyOfValue, class Compare, class Alloc
	= alloc>
class rb_tree {
protected:
	typedef void* void_pointer;
	typedef __rb_tree_node_base* base_ptr;
	typedef __rb_tree_node<Value> rb_tree_node;
	typedef rb_tree_node* link_type;
	typedef Key key_type;
	typedef Value value_type;
public:
	// insert⽤的是第⼆个模板参数左形参
	pair<iterator, bool> insert_unique(const value_type& x);
	// erase和find⽤第⼀个模板参数做形参
	size_type erase(const key_type& x);
	iterator find(const key_type& x);
protected:
	size_type node_count; // keeps track of size of tree
	link_type header;
};
template <class Value>
struct __rb_tree_node : public __rb_tree_node_base
{
	typedef __rb_tree_node<Value>* link_type;
	Value value_field;
};

通过下图对框架的分析，我们可以看到源码中rb_tree⽤了⼀个巧妙的泛型思想实现，rb_tree是实现key的搜索场景，还是key/value的搜索场景不是直接写死的，⽽是由第⼆个模板参数Value决定 _rb_tree_node中存储的数据类型。

set实例化rb_tree时第⼆个模板参数给的是key，map实例化rb_tree时第⼆个模板参数给的是 pair，这样⼀颗红⿊树既可以实现key搜索场景的set，也可以实现key/value搜索场景的map。

要注意⼀下，源码⾥⾯模板参数是⽤T代表value，⽽内部写的value_type不是我们我们⽇常 key/value场景中说的value，源码中的value_type反⽽是红⿊树结点中存储的真实的数据的类型。

rb_tree第⼆个模板参数Value已经控制了红⿊树结点中存储的数据类型，为什么还要传第⼀个模板参数Key呢？尤其是set，两个模板参数是⼀样的，这是很多同学这时的⼀个疑问。要注意的是对于 map和set，find/erase时的函数参数都是Key，所以第⼀个模板参数是传给find/erase等函数做形参的类型的。对于set⽽⾔两个参数是⼀样的，但是对于map⽽⾔就完全不⼀样了，map insert的是pair对象，但是find和ease的是Key对象。

吐槽⼀下，这⾥源码命名⻛格⽐较乱，set模板参数⽤的Key命名，map⽤的是Key和T命名，⽽ rb_tree⽤的⼜是Key和Value，可⻅⼤佬有时写代码也不规范，乱弹琴。

2. 模拟实现map和set

2.1 实现出复⽤红⿊树的框架，并⽀持insert

参考源码框架，map和set复⽤之前我们实现的红⿊树。

我们这⾥相⽐源码调整⼀下，key参数就⽤K，value参数就⽤V，红⿊树中的数据类型，我们使⽤ T。

其次因为RBTree实现了泛型不知道T参数导致是K，还是pair，那么insert内部进⾏插⼊逻辑⽐较时，就没办法进⾏⽐较，因为pair的默认⽀持的是key和value⼀起参与⽐较，我们需要时的任何时候只⽐较key，所以我们在map和set层分别实现⼀个MapKeyOfT和SetKeyOfT的仿函数传给 RBTree的KeyOfT，然后RBTree中通过KeyOfT仿函数取出T类型对象中的key，再进⾏⽐较，具体细节参考如下代码实现。

// 源码中pair⽀持的<重载实现 template <class T1, class T2> bool operator< (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs) { return lhs.first < rhs.first || (!(rhs.first < lhs.first) && lhs.second < rhs.second); }

Mymap.h

namespace xc
{
	template<class K, class V>
	class map
	{
		struct MapKeyOfT
		{
			const K& operator()(const pair<K, V>& kv)
			{
				return kv.first;
			}
		};
	public:
		bool insert(const pair<K, V>& kv)
		{
			return _t.Insert(kv);
		}
	private:
		RBTree<K, pair<K, V>, MapKeyOfT> _t;
	};
}

Myset.h

namespace xc
{
	template<class K>
	class set
	{
		struct SetKeyOfT
		{
			const K& operator()(const K& key)
			{
				return key;
			}
		};
	public:
		bool insert(const K& key)
		{
			return _t.Insert(key);
		}
	private:
		RBTree<K, K, SetKeyOfT> _t;
	};
}

RBTree.h

enum Colour
{
	RED,
	BLACK
};
template<class T>
struct RBTreeNode
{
	T _data;
	RBTreeNode<T>* _left;
	RBTreeNode<T>* _right;
	RBTreeNode<T>* _parent;
	Colour _col;
	RBTreeNode(const T& data)
		: _data(data)
		, _left(nullptr)
		, _right(nullptr)
		, _parent(nullptr)
	{}
};
// 实现步骤：
// 1、实现红⿊树
// 2、封装map和set框架，解决KeyOfT
// 3、iterator
// 4、const_iterator
// 5、key不⽀持修改的问题
// 6、operator[]
template<class K, class T, class KeyOfT>
class RBTree
{
private:
	typedef RBTreeNode<T> Node;
	Node* _root = nullptr;
public:
	bool Insert(const pair<K, V>& kv)
	{
		if (_root == nullptr)
		{
			_root = new Node(kv);
			_root->_col = BLACK;

			return true;
		}

		Node* parent = nullptr;
		Node* cur = _root;
		while (cur)
		{
			if (cur->_kv.first < kv.first)
			{
				parent = cur;
				cur = cur->_right;
			}
			else if (cur->_kv.first > kv.first)
			{
				parent = cur;
				cur = cur->_left;
			}
			else
			{
				return false;
			}
		}

		cur = new Node(kv);
		cur->_col = RED;
		if (parent->_kv.first < kv.first)
		{
			parent->_right = cur;
		}
		else
		{
			parent->_left = cur;
		}
		// 链接父亲
		cur->_parent = parent;

		// 父亲是红色，出现连续的红色节点，需要处理
		while (parent && parent->_col == RED)
		{
			Node* grandfather = parent->_parent;
			if (parent == grandfather->_left)
			{
				//   g
				// p   u
				Node* uncle = grandfather->_right;
				if (uncle && uncle->_col == RED)
				{
					// 变色
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					// 继续往上处理
					cur = grandfather;
					parent = cur->_parent;
				}
				else
				{
					if (cur == parent->_left)
					{
						//     g
						//   p    u
						// c
						RotateR(grandfather);
						parent->_col = BLACK;
						grandfather->_col = RED;
					}
					else
					{
						//      g
						//   p    u
						//     c
						RotateL(parent);
						RotateR(grandfather);
						cur->_col = BLACK;
						grandfather->_col = RED;
					}

					break;
				}
			}
			else
			{
				//   g
				// u   p
				Node* uncle = grandfather->_left;
				// 叔叔存在且为红，-》变色即可
				if (uncle && uncle->_col == RED)
				{
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					// 继续往上处理
					cur = grandfather;
					parent = cur->_parent;
				}
				else // 叔叔不存在，或者存在且为黑
				{
					// 情况二：叔叔不存在或者存在且为黑
					// 旋转+变色
					//   g
					// u   p
					//       c
					if (cur == parent->_right)
					{
						RotateL(grandfather);
						parent->_col = BLACK;
						grandfather->_col = RED;
					}
					else
					{
						RotateR(parent);
						RotateL(grandfather);
						cur->_col = BLACK;
						grandfather->_col = RED;
					}

					break;
				}
			}
		}

		_root->_col = BLACK;

		return true;
	}

	void RotateR(Node * parent)
	{
		Node* subL = parent->_left;
		Node* subLR = subL->_right;

		parent->_left = subLR;
		if (subLR)
			subLR->_parent = parent;

		Node* pParent = parent->_parent;

		subL->_right = parent;
		parent->_parent = subL;

		if (parent == _root)
		{
			_root = subL;
			subL->_parent = nullptr;
		}
		else
		{
			if (pParent->_left == parent)
			{
				pParent->_left = subL;
			}
			else
			{
				pParent->_right = subL;
			}

			subL->_parent = pParent;
		}
	}

	void RotateL(Node * parent)
	{
		Node* subR = parent->_right;
		Node* subRL = subR->_left;
		parent->_right = subRL;
		if (subRL)
			subRL->_parent = parent;

		Node* parentParent = parent->_parent;
		subR->_left = parent;
		parent->_parent = subR;
		if (parentParent == nullptr)
		{
			_root = subR;
			subR->_parent = nullptr;
		}
		else
		{
			if (parent == parentParent->_left)
			{
				parentParent->_left = subR;
			}
			else
			{
				parentParent->_right = subR;
			}
			subR->_parent = parentParent;
		}
	}

};

2.2 ⽀持iterator的实现

iterator核⼼源代码

struct __rb_tree_base_iterator
{
	typedef __rb_tree_node_base::base_ptr base_ptr;
	base_ptr node;
	void increment()
	{
		if (node->right != 0) {
			node = node->right;
			while (node->left != 0)
				node = node->left;
		}
		else {
			base_ptr y = node->parent;
			while (node == y->right) {
				node = y;
				y = y->parent;
			}
			if (node->right != y)
				node = y;
		}
	}
	void decrement()
	{
		if (node->color == __rb_tree_red &&
			node->parent->parent == node)
			node = node->right;
		else if (node->left != 0) {
			base_ptr y = node->left;
			while (y->right != 0)
				y = y->right;
			node = y;
		}
		else {
			base_ptr y = node->parent;
			while (node == y->left) {
				node = y;
				y = y->parent;
			}
			node = y;
		}
	}
};
template <class Value, class Ref, class Ptr>
struct __rb_tree_iterator : public __rb_tree_base_iterator
{
	typedef Value value_type;
	typedef Ref reference;
	typedef Ptr pointer;
	typedef __rb_tree_iterator<Value, Value&, Value*> iterator;
	__rb_tree_iterator() {}
	__rb_tree_iterator(link_type x) { node = x; }
	__rb_tree_iterator(const iterator& it) { node = it.node; }
	reference operator*() const { return link_type(node)->value_field; }
#ifndef __SGI_STL_NO_ARROW_OPERATOR
	pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
	self& operator++() { increment(); return *this; }
	self& operator--() { decrement(); return *this; }
	inline bool operator==(const __rb_tree_base_iterator& x,
		const __rb_tree_base_iterator& y) {
		return x.node == y.node;
	}
	inline bool operator!=(const __rb_tree_base_iterator& x,
		const __rb_tree_base_iterator& y) {
		return x.node != y.node;
	}
};

iterator实现思路分析

iterator实现的⼤框架跟list的iterator思路是⼀致的，⽤⼀个类型封装结点的指针，再通过重载运算符实现，迭代器像指针⼀样访问的⾏为。

这⾥的难点是operator++和operator--的实现。之前使⽤部分，我们分析了，map和set的迭代器⾛的是中序遍历，左⼦树->根结点->右⼦树，那么begin()会返回中序第⼀个结点的iterator也就是10 所在结点的迭代器。

迭代器++的核⼼逻辑就是不看全局，只看局部，只考虑当前中序局部要访问的下⼀个结点。

迭代器++时，如果it指向的结点的右⼦树不为空，代表当前结点已经访问完了，要访问下⼀个结点是右⼦树的中序第⼀个，⼀棵树中序第⼀个是最左结点，所以直接找右⼦树的最左结点即可。

迭代器++时，如果it指向的结点的右⼦树空，代表当前结点已经访问完了且当前结点所在的⼦树也访问完了，要访问的下⼀个结点在当前结点的祖先⾥⾯，所以要沿着当前结点到根的祖先路径向上找。

如果当前结点是⽗亲的左，根据中序左⼦树->根结点->右⼦树，那么下⼀个访问的结点就是当前结点的⽗亲；如下图：it指向25，25右为空，25是30的左，所以下⼀个访问的结点就是30。

如果当前结点是⽗亲的右，根据中序左⼦树->根结点->右⼦树，当前当前结点所在的⼦树访问完了，当前结点所在⽗亲的⼦树也访问完了，那么下⼀个访问的需要继续往根的祖先中去找，直到找到孩⼦是⽗亲左的那个祖先就是中序要问题的下⼀个结点。如下图：it指向15，15右为空，15是10 的右，15所在⼦树话访问完了，10所在⼦树也访问完了，继续往上找，10是18的左，那么下⼀个访问的结点就是18。

end()如何表⽰呢？如下图：当it指向50时，++it时，50是40的右，40是30的右，30是18的右，18 到根没有⽗亲，没有找到孩⼦是⽗亲左的那个祖先，这是⽗亲为空了，那我们就把it中的结点指针置为nullptr，我们⽤nullptr去充当end。需要注意的是stl源码空，红⿊树增加了⼀个哨兵位头结点做为end()，这哨兵位头结点和根互为⽗亲，左指向最左结点，右指向最右结点。相⽐我们⽤ nullptr作为end()，差别不⼤，他能实现的，我们也能实现。只是--end()判断到结点时空，特殊处理⼀下，让迭代器结点指向最右结点。具体参考迭代器--实现。

迭代器--的实现跟++的思路完全类似，逻辑正好反过来即可，因为他访问顺序是右⼦树->根结点-> 左⼦树，具体参考下⾯代码实现。

set的iterator也不⽀持修改，我们把set的第⼆个模板参数改成const K即可， RBTree _t;

map的iterator不⽀持修改key但是可以修改value，我们把map的第⼆个模板参数pair的第⼀个参数改成const K即可， RBTree, MapKeyOfT> _t;

⽀持完整的迭代器还有很多细节需要修改，具体参考下⾯题的代码。

#pragma once
#include <iostream>
using namespace std;
enum Colour
{
	RED,
	BLACK
};
template<class T>
struct RBTreeNode
{
	T _data;
	RBTreeNode<T>* _left;
	RBTreeNode<T>* _right;
	RBTreeNode<T>* _parent;
	Colour _col;
	RBTreeNode(const T& data)
		:_data(data)
		, _left(nullptr)
		, _right(nullptr)
		, _parent(nullptr)
	{}
};
//迭代器
template <class T,class Ref,class Ptr>
struct RBTreeIterator
{
	typedef RBTreeNode<T>Node;
	typedef RBTreeIterator<T, Ref, Ptr>Self;
	Node* _node;
	Node* _root;
	RBTreeIterator(Node* node, Node* root)
		:_node(node)
		, _root(root)
	{}
	//返回迭代器类型
	Self operator++()
	{
		if (_node->_right)
		{
			//右不为空，中序下一个访问的节点是右子树的最左(最小)节点
			Node* min = _node->_right;
			while (min->_left)
			{
				min = min->_left;
			}
			_node = min;
		}
		else
		{
			//右为空，祖先里面孩子是父亲左的那个祖先
			Node* cur = _node;
			Node* parent = cur->_parent;
			while (parent && cur == parent->_right)
			{
				cur = parent;
				parent = cur->_parent;
			}
			_node = parent;
		}
		return *this;
	}
	Self operator--()
	{
		if (_node == nullptr)//--end()
		{
			// --end()，特殊处理，走到中序最后一个结点，整棵树的最右结点
			Node* rightMost = _root;
			while (rightMost && rightMost->_right)
			{
				rightMost = rightMost->_right;
			}
			_node = rightMost;
		}
		else if (_node->_left)
		{
			//左子树不为空，中序左子树最后一个
			Node* rightMost = _node->_left;
			while (rightMost->_right)
			{
				rightMost = rightMost->_right;
			}
			_node = rightMost;
		}
		else
		{
			//孩子是父亲右的那个祖先
			Node* cur = _node;
			Node* parent = cur->_parent;
			while (parent && cur == parent->_left)
			{
				cur = parent;
				parent = cur->_parent;
			}
			_node = parent;
		}
		return *this;
	}
	
	
	//返回值
	Ref operator*()
	{
		return _node->_data;
	}
	//返回引用
	Ptr operator->()
	{
		return &_node->_data;
	}
	bool operator != (const Self& s)const
	{
		return _node != s._node;
	}
	bool operator == (const Self& s)const
	{
		return _node == s._node;
	}

};
//第一个参数是key，第二个参数是pair，第三个参数是仿函数
template<class K, class T,class KeyOfT>
class RBTree
{
	typedef RBTreeNode<T> Node;
public:
	typedef RBTreeIterator<T, T&, T*> Iterator;
	//const T&，表示解引用迭代器时返回的是一个对 T 类型常量的引用，因此无法修改元素的值。
	//const T* 是一个指向常量类型 T 的指针，意味着你不能通过该指针修改它指向的数据
	typedef RBTreeIterator<T, const T&, const T*>ConstIterator;
	Iterator Begin()
	{
		Node* cur = _root;
		while (cur && cur->_left)
		{
			cur = cur->_left;
		}
		return Iterator(cur,_root);
	}
	Iterator End()
	{
		return Iterator(nullptr, _root);
	}
	ConstIterator Begin() const
	{
		Node* cur = _root;
		while (cur && cur->_left)
		{
			cur = cur->_left;
		}
		return ConstIterator(cur, _root);
	}
	ConstIterator End() const
	{
		return ConstIterator(nullptr, _root);
	}
	//默认构造函数声明，告知编译器自动生成一个默认的构造函数。
	RBTree() = default;

	//深拷贝
	RBTree(const RBTree& t)
	{
		_root = Copy(t._root);
	}

	//赋值
	RBTree& operator=(RBTree t)
	{
		swap(_root, t._root);
		return *this;
	}

	//析构
	~RBTree()
	{
		Destroy(_root);
		_root = nullptr;
	}
	pair<Iterator,bool> Insert(const T & data)
	{
		if (_root == nullptr)
		{
			_root = new Node(data);
			_root->_col = BLACK;
			return { Iterator(_root,_root),true };
		}
		KeyOfT kot;
		Node* parent = nullptr;
		Node* cur = _root;
		while (cur)
		{
			if (kot(cur->_data) < kot(data))
			{
				parent = cur;
				cur = cur->_right;
			}
			else if (kot(cur->_data) > kot(data))
			{
				parent = cur;
				cur = cur->_left;
			}
			else
			{
				return { Iterator(_root,_root),false };
			}
		}
		cur = new Node(data);
		Node* newnode = cur;
		cur->_col = RED;
		
		if (kot(parent->_data) > kot(data))
		{
			parent->_left = cur;
		}
		else
		{
			parent->_right = cur;
		}
		//链接父节点
		cur->_parent = parent;
		cur->_col = RED;
		//父亲是红色，出现链接的红色节点，需要处理
		while (parent && parent->_col == RED)
		{
			Node* grandfather = parent->_parent;
			if (parent == grandfather->_left)
			{
				//   g
				// p   u
				//u可能为空,避免空指针解引用(叔叔)
				Node* uncle = grandfather->_right;
				if (uncle && uncle->_col == RED)
				{
					//变色
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					//继续往上处理
					cur = grandfather;
					parent = cur->_parent;

				}
				else
				{
					if (cur == parent->_left)
					{
						//     g
						//   p    u
						// c
						RotateR(grandfather);
						parent->_col = BLACK;
						grandfather->_col = RED;
					}
					else
					{
						//      g
						//   p    u
						//     c
						RotateL(parent);
						RotateR(grandfather);
						grandfather->_col = RED;
						cur->_col = BLACK;
					}
					break;
				}
			}
			// 叔叔不存在，或者存在且为黑
			else
			{
				//   g
				// u   p
				// 叔叔存在且为红，-》变色即可
				Node* uncle = grandfather->_left;
				if (uncle && uncle->_col == RED)
				{
					//变色
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					//向上更新
					cur = grandfather;
					parent = grandfather->_parent;

				}
				// 叔叔不存在，或者存在且为黑
				else
				{
					// 情况二：叔叔不存在或者存在且为黑
					// 旋转+变色
					//   g
					// u   p
					//       c
					if (cur == parent->_right)
					{
						RotateL(grandfather);
						parent->_col = BLACK;
						cur->_col = grandfather->_col = RED;

					}
					//   g
					// u   p
					//   c
					else
					{
						RotateR(parent);
						RotateL(grandfather);
						cur->_col = BLACK;
						grandfather->_col = RED;
					}
					break;

				}
			}
		}
		_root->_col = BLACK;
		return { Iterator(newnode,_root),true };
	}
	void RotateR(Node * parent)
	{
		Node* subL = parent->_left;
		Node* subLR = subL->_right;

		parent->_left = subLR;
		if (subLR)
			subLR->_parent = parent;

		Node* pParent = parent->_parent;

		subL->_right = parent;
		parent->_parent = subL;

		if (parent == _root)
		{
			_root = subL;
			subL->_parent = nullptr;
		}
		else
		{
			if (pParent->_left == parent)
			{
				pParent->_left = subL;
			}
			else
			{
				pParent->_right = subL;
			}

			subL->_parent = pParent;
		}
	}

	void RotateL(Node * parent)
	{
		Node* subR = parent->_right;
		Node* subRL = subR->_left;
		parent->_right = subRL;
		if (subRL)
			subRL->_parent = parent;

		Node* parentParent = parent->_parent;
		subR->_left = parent;
		parent->_parent = subR;
		if (parentParent == nullptr)
		{
			_root = subR;
			subR->_parent = nullptr;
		}
		else
		{
			if (parent == parentParent->_left)
			{
				parentParent->_left = subR;
			}
			else
			{
				parentParent->_right = subR;
			}
			subR->_parent = parentParent;
		}
	}
	Iterator* Find(const K & key)
	{
		Node* cur = _root;
		while (cur)
		{
			if (cur->_kv.first < key)
			{
				cur = cur->_right;
			}
			else if (cur->_kv.first > key)
			{
				cur = cur->_left;
			}
			else
			{
				return Iterator(cur,_root);
			}

		}
		return End();
	}
private:
	void Destroy(Node* root)
	{
		if (root == nullptr)
			return;
		Destroy(root->_left);
		Destroy(root->_right);
		delete root;
	}
	Node* Copy(Node* root)
	{
		if (root == nullptr)
			return nullptr;

		Node* newRoot = new Node(root->_data);
		newRoot->_col = root->_col;//确保颜色也被复制
		newRoot->_left = Copy(root->_left);//递归复制左子树
		newRoot->_right = Copy(root->_right);//递归复制右子树

		//左子树不为空，设置父节点
		if (newRoot->_left)
			newRoot->_left->_parent = newRoot;

		//右子树不为空，设置父节点
		if(newRoot->_right)
			newRoot->_right->_parent = newRoot;

		return newRoot;
	}
private:
	Node* _root = nullptr;
};

Mymap

#pragma once
#include "RBTree.h"
namespace xc
{
	template<class K,class V>
	class map
	{
		struct MapKeyOfT
		{
			const K& operator()(const pair<K, V>& kv)
			{
				return kv.first;
			}
		};
	public:
		typedef typename RBTree<K, pair<const K,V>, MapKeyOfT>::Iterator iterator;
		typedef typename RBTree<K, pair<const K, V>, MapKeyOfT>::ConstIterator const_iterator;
		iterator begin()
		{
			return _t.Begin();
		}
		iterator end()
		{
			return _t.End();
		}
		const_iterator begin() const
		{
			return _t.Begin();
		}
		const_iterator end() const
		{
			return _t.End();
		}
		pair<iterator, bool> insert(const pair<K, V>& kv)
		{
			return _t.Insert(kv);
		}
		
	private:
		RBTree<K, pair<const K, V>, MapKeyOfT> _t;
	};
}

Myset

#pragma once
#include "RBTree.h"
namespace xc
{
	//仿函数
	template<class K>
	class set
	{
		struct SetKeyOfT
		{
			const K& operator()(const K& key)
			{
				return key;
			}
		};
	public:
		typedef typename RBTree<K, const K, SetKeyOfT>::Iterator iterator;
		typedef typename RBTree<K, const K, SetKeyOfT>::ConstIterator const_iterator;
		iterator begin()
		{
			return _t.Begin();
		}
		iterator end()
		{
			return _t.End();
		}
		const_iterator begin() const 
		{
			return _t.Begin();
		}
		const_iterator end() const
		{
			return _t.End();
		}
		
		pair<iterator,bool> insert(const K& key)
		{
			return _t.Insert(key);
		}
	private:
		RBTree<K, const K, SetKeyOfT> _t;
	};
}

2.3 map⽀持[]

map要⽀持[]主要需要修改insert返回值⽀持，修改RBtree中的insert返回值为 pair Insert(const T& data)

有了insert⽀持[]实现就很简单了，具体参考下⾯代码实现

V& operator[](const K& key)
{
	pair<iterator, bool>ret = insert({ key,V() });
	return ret.first->second;
}

3.所有代码

RBTree

#pragma once
#include <iostream>
using namespace std;
enum Colour
{
	RED,
	BLACK
};
template<class T>
struct RBTreeNode
{
	T _data;
	RBTreeNode<T>* _left;
	RBTreeNode<T>* _right;
	RBTreeNode<T>* _parent;
	Colour _col;
	RBTreeNode(const T& data)
		:_data(data)
		, _left(nullptr)
		, _right(nullptr)
		, _parent(nullptr)
	{}
};
//迭代器
template <class T,class Ref,class Ptr>
struct RBTreeIterator
{
	typedef RBTreeNode<T>Node;
	typedef RBTreeIterator<T, Ref, Ptr>Self;
	Node* _node;
	Node* _root;
	RBTreeIterator(Node* node, Node* root)
		:_node(node)
		, _root(root)
	{}
	//返回迭代器类型
	Self operator++()
	{
		if (_node->_right)
		{
			//右不为空，中序下一个访问的节点是右子树的最左(最小)节点
			Node* min = _node->_right;
			while (min->_left)
			{
				min = min->_left;
			}
			_node = min;
		}
		else
		{
			//右为空，祖先里面孩子是父亲左的那个祖先
			Node* cur = _node;
			Node* parent = cur->_parent;
			while (parent && cur == parent->_right)
			{
				cur = parent;
				parent = cur->_parent;
			}
			_node = parent;
		}
		return *this;
	}
	Self operator--()
	{
		if (_node == nullptr)//--end()
		{
			// --end()，特殊处理，走到中序最后一个结点，整棵树的最右结点
			Node* rightMost = _root;
			while (rightMost && rightMost->_right)
			{
				rightMost = rightMost->_right;
			}
			_node = rightMost;
		}
		else if (_node->_left)
		{
			//左子树不为空，中序左子树最后一个
			Node* rightMost = _node->_left;
			while (rightMost->_right)
			{
				rightMost = rightMost->_right;
			}
			_node = rightMost;
		}
		else
		{
			//孩子是父亲右的那个祖先
			Node* cur = _node;
			Node* parent = cur->_parent;
			while (parent && cur == parent->_left)
			{
				cur = parent;
				parent = cur->_parent;
			}
			_node = parent;
		}
		return *this;
	}
	
	
	//返回值
	Ref operator*()
	{
		return _node->_data;
	}
	//返回引用
	Ptr operator->()
	{
		return &_node->_data;
	}
	bool operator != (const Self& s)const
	{
		return _node != s._node;
	}
	bool operator == (const Self& s)const
	{
		return _node == s._node;
	}

};
//第一个参数是key，第二个参数是pair，第三个参数是仿函数
template<class K, class T,class KeyOfT>
class RBTree
{
	typedef RBTreeNode<T> Node;
public:
	typedef RBTreeIterator<T, T&, T*> Iterator;
	//const T&，表示解引用迭代器时返回的是一个对 T 类型常量的引用，因此无法修改元素的值。
	//const T* 是一个指向常量类型 T 的指针，意味着你不能通过该指针修改它指向的数据
	typedef RBTreeIterator<T, const T&, const T*>ConstIterator;
	Iterator Begin()
	{
		Node* cur = _root;
		while (cur && cur->_left)
		{
			cur = cur->_left;
		}
		return Iterator(cur,_root);
	}
	Iterator End()
	{
		return Iterator(nullptr, _root);
	}
	ConstIterator Begin() const
	{
		Node* cur = _root;
		while (cur && cur->_left)
		{
			cur = cur->_left;
		}
		return ConstIterator(cur, _root);
	}
	ConstIterator End() const
	{
		return ConstIterator(nullptr, _root);
	}
	//默认构造函数声明，告知编译器自动生成一个默认的构造函数。
	RBTree() = default;

	//深拷贝
	RBTree(const RBTree& t)
	{
		_root = Copy(t._root);
	}

	//赋值
	RBTree& operator=(RBTree t)
	{
		swap(_root, t._root);
		return *this;
	}

	//析构
	~RBTree()
	{
		Destroy(_root);
		_root = nullptr;
	}
	pair<Iterator,bool> Insert(const T & data)
	{
		if (_root == nullptr)
		{
			_root = new Node(data);
			_root->_col = BLACK;
			return { Iterator(_root,_root),true };
		}
		KeyOfT kot;
		Node* parent = nullptr;
		Node* cur = _root;
		while (cur)
		{
			if (kot(cur->_data) < kot(data))
			{
				parent = cur;
				cur = cur->_right;
			}
			else if (kot(cur->_data) > kot(data))
			{
				parent = cur;
				cur = cur->_left;
			}
			else
			{
				return { Iterator(_root,_root),false };
			}
		}
		cur = new Node(data);
		Node* newnode = cur;
		cur->_col = RED;
		
		if (kot(parent->_data) > kot(data))
		{
			parent->_left = cur;
		}
		else
		{
			parent->_right = cur;
		}
		//链接父节点
		cur->_parent = parent;
		cur->_col = RED;
		//父亲是红色，出现链接的红色节点，需要处理
		while (parent && parent->_col == RED)
		{
			Node* grandfather = parent->_parent;
			if (parent == grandfather->_left)
			{
				//   g
				// p   u
				//u可能为空,避免空指针解引用(叔叔)
				Node* uncle = grandfather->_right;
				if (uncle && uncle->_col == RED)
				{
					//变色
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					//继续往上处理
					cur = grandfather;
					parent = cur->_parent;

				}
				else
				{
					if (cur == parent->_left)
					{
						//     g
						//   p    u
						// c
						RotateR(grandfather);
						parent->_col = BLACK;
						grandfather->_col = RED;
					}
					else
					{
						//      g
						//   p    u
						//     c
						RotateL(parent);
						RotateR(grandfather);
						grandfather->_col = RED;
						cur->_col = BLACK;
					}
					break;
				}
			}
			// 叔叔不存在，或者存在且为黑
			else
			{
				//   g
				// u   p
				// 叔叔存在且为红，-》变色即可
				Node* uncle = grandfather->_left;
				if (uncle && uncle->_col == RED)
				{
					//变色
					parent->_col = uncle->_col = BLACK;
					grandfather->_col = RED;

					//向上更新
					cur = grandfather;
					parent = grandfather->_parent;

				}
				// 叔叔不存在，或者存在且为黑
				else
				{
					// 情况二：叔叔不存在或者存在且为黑
					// 旋转+变色
					//   g
					// u   p
					//       c
					if (cur == parent->_right)
					{
						RotateL(grandfather);
						parent->_col = BLACK;
						cur->_col = grandfather->_col = RED;

					}
					//   g
					// u   p
					//   c
					else
					{
						RotateR(parent);
						RotateL(grandfather);
						cur->_col = BLACK;
						grandfather->_col = RED;
					}
					break;

				}
			}
		}
		_root->_col = BLACK;
		return { Iterator(newnode,_root),true };
	}
	void RotateR(Node * parent)
	{
		Node* subL = parent->_left;
		Node* subLR = subL->_right;

		parent->_left = subLR;
		if (subLR)
			subLR->_parent = parent;

		Node* pParent = parent->_parent;

		subL->_right = parent;
		parent->_parent = subL;

		if (parent == _root)
		{
			_root = subL;
			subL->_parent = nullptr;
		}
		else
		{
			if (pParent->_left == parent)
			{
				pParent->_left = subL;
			}
			else
			{
				pParent->_right = subL;
			}

			subL->_parent = pParent;
		}
	}

	void RotateL(Node * parent)
	{
		Node* subR = parent->_right;
		Node* subRL = subR->_left;
		parent->_right = subRL;
		if (subRL)
			subRL->_parent = parent;

		Node* parentParent = parent->_parent;
		subR->_left = parent;
		parent->_parent = subR;
		if (parentParent == nullptr)
		{
			_root = subR;
			subR->_parent = nullptr;
		}
		else
		{
			if (parent == parentParent->_left)
			{
				parentParent->_left = subR;
			}
			else
			{
				parentParent->_right = subR;
			}
			subR->_parent = parentParent;
		}
	}
	int Size()
	{
		return _Size(_root);
	}
	int Height()
	{
		return _Height(_root);
	}
	Iterator* Find(const K & key)
	{
		Node* cur = _root;
		while (cur)
		{
			if (cur->_kv.first < key)
			{
				cur = cur->_right;
			}
			else if (cur->_kv.first > key)
			{
				cur = cur->_left;
			}
			else
			{
				return Iterator(cur,_root);
			}

		}
		return End();
	}
private:
	int _Height(Node * root)
	{
		if (root == nullptr)
			return 0;
		int leftHeight = _Height(root->_left);
		int rightHeight = Height(root->_right);
		return leftHeight > rightHeight ? leftHeight + 1 : rightHeight + 1;
	}
	int _Size(Node * root)
	{
		if (root == nullptr)
			return 0;

		return _Size(root->_left) + _Size(root->_right) + 1;
	}
	void Destroy(Node* root)
	{
		if (root == nullptr)
			return;
		Destroy(root->_left);
		Destroy(root->_right);
		delete root;
	}
	Node* Copy(Node* root)
	{
		if (root == nullptr)
			return nullptr;

		Node* newRoot = new Node(root->_data);
		newRoot->_col = root->_col;//确保颜色也被复制
		newRoot->_left = Copy(root->_left);//递归复制左子树
		newRoot->_right = Copy(root->_right);//递归复制右子树

		//左子树不为空，设置父节点
		if (newRoot->_left)
			newRoot->_left->_parent = newRoot;

		//右子树不为空，设置父节点
		if(newRoot->_right)
			newRoot->_right->_parent = newRoot;

		return newRoot;
	}
private:
	Node* _root = nullptr;
};

Myset

#pragma once
#include "RBTree.h"
namespace xc
{
	//仿函数
	template<class K>
	class set
	{
		struct SetKeyOfT
		{
			const K& operator()(const K& key)
			{
				return key;
			}
		};
	public:
		typedef typename RBTree<K, const K, SetKeyOfT>::Iterator iterator;
		typedef typename RBTree<K, const K, SetKeyOfT>::ConstIterator const_iterator;
		iterator begin()
		{
			return _t.Begin();
		}
		iterator end()
		{
			return _t.End();
		}
		const_iterator begin() const 
		{
			return _t.Begin();
		}
		const_iterator end() const
		{
			return _t.End();
		}
		
		pair<iterator,bool> insert(const K& key)
		{
			return _t.Insert(key);
		}
	private:
		RBTree<K, const K, SetKeyOfT> _t;
	};
}

Mymap

#pragma once
#include "RBTree.h"
namespace xc
{
	template<class K,class V>
	class map
	{
		struct MapKeyOfT
		{
			const K& operator()(const pair<K, V>& kv)
			{
				return kv.first;
			}
		};
	public:
		typedef typename RBTree<K, pair<const K,V>, MapKeyOfT>::Iterator iterator;
		typedef typename RBTree<K, pair<const K, V>, MapKeyOfT>::ConstIterator const_iterator;
		iterator begin()
		{
			return _t.Begin();
		}
		iterator end()
		{
			return _t.End();
		}
		const_iterator begin() const
		{
			return _t.Begin();
		}
		const_iterator end() const
		{
			return _t.End();
		}
		pair<iterator, bool> insert(const pair<K, V>& kv)
		{
			return _t.Insert(kv);
		}
		V& operator[](const K& key)
		{
			pair<iterator, bool>ret = insert({ key,V() });
			return ret.first->second;
		}
		
	private:
		RBTree<K, pair<const K, V>, MapKeyOfT> _t;
	};
}

Test.cpp

#define _CRT_SECURE_NO_WARNINGS 1
#include "Mymap.h"
#include "Myset.h"
void Print(const xc::set<int>& s)
{
	xc::set<int>::const_iterator it = s.end();
	while (it != s.begin())
	{
		--it;
		cout << *it << " ";
	}
	cout << endl;
}
int main()
{
	xc::set<int> s;
	s.insert(18);
	s.insert(10);
	s.insert(15);
	s.insert(30);
	s.insert(35);
	s.insert(50);
	s.insert(40);
	s.insert(25);

	xc::set<int>::iterator sit = s.begin();
	//*sit += 10;
	while (sit != s.end())
	{
		cout << *sit << " ";
		++sit;
	}
	cout << endl;

	for (auto& e : s)
	{
		cout << e << " ";
	}
	cout << endl;

	

	/*xc::set<int> s1(s);
	auto it = s1.begin();
	while (it != s.end())
	{
		cout << *it << " ";
		++it;
	}
	cout << endl;*/

	xc::map<string, string> dict;
	dict.insert({ "sort", "排序" });
	dict.insert({ "left", "左边" });
	dict.insert({ "right", "右边" });

	dict["left"] = "左边，剩余";
	dict["insert"] = "插入";
	dict["string"];

	xc::map<string, string>::iterator it = dict.begin();
	while (it != dict.end())
	{
		// 不能修改first，可以修改second
		//it->first += 'x';
		//it->second += 'x';

		cout << it->first << ":" << it->second << endl;
		++it;
	}
	cout << endl;

	/*xc::map<string, string> dict1(dict);
	auto it2 = dict1.begin();
	while (it2 != dict1.end())
	{
		cout << it2->first << ":" << it2->second << endl;
		++it2;
	}
	cout << endl;*/


	return 0;
}