# include<iostream>
using namespace std;
template<class K,class V>
struct AVLTreeNode
{
	AVLTreeNode *_parent;
	AVLTreeNode *_right;
	AVLTreeNode *_left;
	K key;
	V value;
	int _bf;//定义平衡因子
	AVLTreeNode(const K&key,const V&value)
		:_parent(NULL)
		, _right(NULL)
		, _left(NULL)
		, _key(key )
		, _value(value)
		, _bf(0)
	{}
};
template<class K,class V>
class AVLTree
{
typedef AVLTreeNode<K,V> Node;
private:
Node *_root;
public:
	AVLTree()
		:_root(NULL)
	{}
	bool Insert(const K&key, const V&value)
	{
		//将节点插成二叉搜索树
		if (_root == NULL)
		{
			_root = new Node(key, value);
			return true;
		}
		Node *cur =_root;
		Node *parent = NULL;
		while (cur)
		{
			if (key > cur->key)
			{ 
				parent = cur;
				cur = cur->_right;
			}
			else if (key<cur->key)
			{
				parent = cur;
				cur = cur->_left;
			}
			else 
			{
				return false;
			}
			cur = new Node(key, value);
			if (key>parent->key)
			{
				parent->_right = cur;
				cur->_parent = parent;
			}
			else
			{
				parent->_left = cur;
				cur->_parent = parent;
			}
		}

//调整平衡因子
		bool IsRotate = false;
		while (parent)
		{
			if (cur == parent->_left)
			{
				parent->_bf--;
			}
			else
			{
				parent->_bf++;
			}
			if (parent->_bf == 0)//程序能进入这里，这说明插入节点失败，不用调整平衡直接退出
			{
				break;
			}
			else if (parent->_bf == 1 || parent->_bf == -1)
			{
				cur = parent;
				parent = parent->_parent;
			}
			else//parent为2或-2的情况
			{
				IsRotate = true;
				if (parent->_bf == 2)
				{
					if (cur->_bf == 1)
					{
						RotateL(parent);//左单旋转
					}
					if (cur->_bf == -1)
					{
						RotateRL(parent);//先右后左双旋转
					}
				}
				else//也就是parent->_bf==-2的情况
				{
					if (cur->_bf == -1)
					{
						RotateR(parent);//右单旋转
					}
					if (cur->_bf == 1)
					{
						RotateLR(parent);//先左后右双旋转
					}
				}
				break;
			}
		}
		if (IsRotate)
		{
			Node* GrandParent = parent->_parent;
			if (GrandParent == NULL)
			{
				_root = parent;
			}
			else
			{
				if (parent->_key < GrandParent->_key)
				{
					GrandParent->_left = parent;
				}
				else
				{
					GrandParent->_right = parent;
				}
			}
		}
		return true;
	}
};