//AVLTree.h

#pragma once

template<class K,class V>
struct AVLTreeNode
{
	AVLTreeNode<K,V>* _left;
	AVLTreeNode<K,V>* _right;
	AVLTreeNode<K,V>* _parent;

	K _key;
	V _value;
	int _bf;

	AVLTreeNode(const K& key,const V& value)
		:_left(NULL),_right(NULL),_parent(NULL),_key(key),_value(value),_bf(0)
	{}
};

template<class K,class V>
class AVLTree
{
	typedef AVLTreeNode<K,V> Node;
public:
	AVLTree()
		:_root(NULL)
	{}

	bool Insert(const K& key,const V& value)
	{
		//插入节点
		if(_root == NULL)
		{
			_root = new Node(key,value);
		}
		Node* cur = _root;
		Node* parent = NULL;
		while(cur)
		{
			if(cur->_key < key)
			{
				parent = cur;
				cur = cur->_right;
			}
			else if(cur->_key > key)
			{
				parent = cur;
				cur = cur->_left;
			}
			else
				return false;
		}
		cur = new Node(key,value);
		if(parent->_key < key)
		{
			parent->_right = cur;
			cur->_parent = parent;
		}
		else
		{
			parent->_left = cur;
			cur->_parent = parent;
		}

		//更新平衡因子
		while(parent)
		{
			//右孩子平衡因子加1，左孩子平衡因子减1
			if(parent->_right == cur)
				parent->_bf ++;
			else if(parent->_left == cur)
				parent->_bf --;
	
			if(parent->_bf == 0)
				break;
			else if(parent->_bf == 1 || parent->_bf == -1)
			{
				cur = parent;
				parent = cur->_parent;
			}
			else	//_bf = 2 || -2
			{
				if(parent->_bf == 2)	//parent->_bf == 2
				{
					if(cur->_bf == 1)
						RotateL(parent);
					else	//_bf = -1
						RotateRL(parent);
				}
				else if(parent->_bf == -2)	//parent->_bf == -2
				{
					if(cur->_bf == -1)
						RotateR(parent);
					else	//_bf = 1
						RotateLR(parent);
				}
				return true;
			}
		}
		return true;
	}
	void RotateL(Node* parent)
	{
		Node* subR = parent->_right;
		Node* subRL = subR->_left;
		parent->_right = subRL;
		if(subRL)
		{
			subRL->_parent = parent;
		}
		subR->_left = parent;
		Node* ppNode = parent->_parent;
		parent->_parent = subR;

		if(ppNode == NULL)
		{
			_root = subR;
			subR->_parent = NULL;
		}
		else
		{
			if(ppNode->_left == parent)
			{
				ppNode->_left = subR;
				subR->_parent = ppNode;
			}
			else
			{
				ppNode->_right = subR;
				subR->_parent = ppNode;
			}
		}
		subR->_bf = parent->_bf = 0;
	}
	void RotateR(Node* parent)
	{
		Node* subL = parent->_left;
		Node* subLR = subL->_right;
		parent->_left = subLR;
		if(subLR)
		{
			subLR->_parent = parent;
		}
		subL->_right = parent;

		Node* ppNode = parent->_parent;
		parent->_parent = subL;
		
		//判断parent是否有父亲节点
		if(ppNode == NULL)
		{
			_root = subL;
			subL->_parent = NULL;
		}
		else
		{
			if(ppNode->_left == parent)
			{
				ppNode->_left = subL;
				subL->_parent = ppNode;
			}
			else
			{
				ppNode->_right = subL;
				subL->_parent = ppNode;
			}
		}
		subL->_bf = parent->_bf = 0;
	}
	void RotateRL(Node* parent)
	{
		Node* subR = parent->_right;
		Node* subRL = subR->_left;
		int bf = subRL->_bf;

		RotateR(parent->_right);
		RotateL(parent);

		if(bf == 1)
		{
			subR->_bf = 0;
			parent->_bf = -1;
		}
		else if(bf == -1)
		{
			parent->_bf = 0;
			subR->_bf = 1;
		}
		else
		{
			subR->_bf = parent->_bf = 0;
		}
		subRL->_bf = 0;
	}
	void RotateLR(Node* parent)
	{
		Node* subL = parent->_left;
		Node* subLR = subL->_right;
		int bf = subLR->_bf;

		RotateL(parent->_left);
		RotateR(parent);

		if(bf == 1)
		{
			subL->_bf = -1;
			parent->_bf = 0;
		}
		else if(bf == -1)
		{
			parent->_bf = 1;
			subL->_bf = 0;
		}
		else 
		{
			subL->_bf = parent->_bf = 0;
		}
		subLR->_bf = 0;
	}

	void InOrder()
	{
		_InOrder(_root);
		cout<<endl;
	}

	int Height(Node* root)
	{
		if(root == NULL)
		{
			return 0;
		}
		int left = Height(root->_left);
		int right = Height(root->_right);

		return left > right ? (left+1) : (right+1); 
	}

	bool IsBlance()
	{
		return _IsBlance(_root);
	}

	bool _IsBlance(Node* root)
	{
		if(root == NULL)
		{
			return true;
		}
		int left = Height(root->_left);
		int right = Height(root->_right);

		if((right-left) != root->_bf)
		{
			cout<<"平衡因子异常"<<root->_key<<endl;
			return false;
		}
		return abs(right-left < 2)
			&& _IsBlance(root->_left)
			&& _IsBlance(root->_right);
	}

	void _InOrder(Node* root)
	{
		if(root == NULL)
		{
			return;
		}
		_InOrder(root->_left);
		cout<<root->_key<<" ";
		_InOrder(root->_right);
	}

protected:
	Node* _root;
};

void TestTree()
{
	AVLTree<int,int> tree;
	int a[]={16,3,7,11,9,26,18,14,15};
	for(size_t i = 0; i < sizeof(a)/sizeof(a[0]); ++i)
	{
		tree.Insert(a[i],i);
	}
	tree.InOrder();
	cout<<"Blance?"<<tree.IsBlance()<<endl;
	getchar();
}

void TestTree1()
{
	AVLTree<int,int> tree1;
	int array1[]={4,2,6,1,5,15,16,14};
	for(size_t i = 0; i < sizeof(array1)/sizeof(array1[0]); ++i)
	{
		tree1.Insert(array1[i],i);
	}
	tree1.InOrder();
	cout<<"Blance?"<<tree1.IsBlance()<<endl;
	getchar();
}

//Test.cpp

#include<iostream>
using namespace std;

#include"AVLTree.h"

int main()
{
	//TestTree();
	TestTree1();
	getchar();
	return 0;
}