数据结构之AVLTree（04-1：Root of AVL Tree）

// Root_of_AVL_Tree.cpp : Defines the entry point for the console application.
//


#include "stdafx.h"
#include <stdlib.h>
#include <conio.h>
#include <stdio.h>
#define MAX 50
int length=0;
typedef  struct  node
{
int data;
struct  node *left;
struct  node *right;
}TREE;




/*
void LevelOrderTranversal(TREE * tree){


Queue q;
InitQueue(&q);
if(!tree) return;
EnQueue(&q,tree->data);
while(!IsQueueEmpty(&q))
{int tmp=DeQueue(&q);
if(tree->left) EnQueue(&q,tree->left->data);
if(tree->right) EnQueue(&q,tree->right->data);
}


}
*/

//把数组方式的二叉树变成链表形式，这里没用到
TREE *createTree(int * data,int pos){


if(pos>length||data[pos]==0)
return NULL;
   TREE* tree=NULL;
tree=(TREE *) malloc(sizeof(TREE));
tree->data=data[pos];
tree->left=createTree(data,2*pos+1);
tree->right=createTree(data,2*pos+2);


return tree;


}


void printTree(TREE * tree){
if(tree)
{printf("%d",tree->data);
printTree(tree->left);
printTree(tree->right);
}
}
int level(TREE * tree)
{
int l=0,r=0,maxH=0;
int i=0;
if(tree)
{
l=level(tree->left);
r=level(tree->right);
maxH=l>r?l:r;
return maxH+1;
}else
return 0;




}
int isBalanced(TREE * tree){
int flag=1;
if(abs(level(tree->left)-level(tree->right))==2)
flag=0;
else
flag=1;
return flag;
}
void changeToAVLTree(TREE * tree)
{
if(!isBalanced(tree))
  changeToAVLTree(tree->left);


}
TREE * SingleLeftRotation(TREE * tree)
{
TREE * b=tree->left;
tree->left=b->right;
b->right=tree;
return b;
}


TREE * SingleRightRotation(TREE * tree)
{
TREE * b=tree->right;
tree->right=b->left;
b->left=tree;
return b;
}
TREE * DoubleLeftRightRotation(TREE * tree)
{
tree->left=SingleRightRotation(tree->left);
return SingleLeftRotation(tree);
}
TREE * DoubleRightLeftRotation(TREE * tree)
{
tree->right=SingleLeftRotation(tree->right);
return SingleRightRotation(tree);
}
////递归方法插入节点
TREE * insert(TREE * root, int x)
{
    
    
    if(root == NULL){
TREE* p = (TREE*)malloc(sizeof(TREE));
p->data = x;
    p->left = NULL;
    p->right = NULL;
        root = p;    
    }    
    else if(x < root->data){
        root->left = insert(root->left, x);    
if(abs(level(root->left)-level(root->right))==2)

if(x<root->left->data)
root=SingleLeftRotation(root);
else
root=DoubleLeftRightRotation(root);
    }
    else{
        root->right = insert(root->right, x);  
if(abs(level(root->left)-level(root->right))==2)
if(x>root->right->data)
root=SingleRightRotation(root);
else
root=DoubleRightLeftRotation(root);
    }
    return root;
}


int main()
{  
 int data[MAX]={0};              //0 为设定的初始值，
int i=0;                  
scanf("%d",&length);
while(i<length)
{
         scanf("%d",&data[i]);
i++;
}
TREE * tree=0;
for(i=0;i<length;i++){
tree=insert(tree,data[i]);
}
printTree(tree);
//TREE * tree=createTree(data,0);



   


  
    return 0;
}