39、平衡二叉树

题目描述
输入一棵二叉树，判断该二叉树是否是平衡二叉树。

class Solution {
public:
    bool IsBalanced_Solution(TreeNode* pRoot) {
        if(pRoot==NULL)
            return true;
        int leftTree = TreeDepth(pRoot->left);
        int rightTree = TreeDepth(pRoot->right);
        if(abs(leftTree-rightTree)>1)
            return false;
        return IsBalanced_Solution(pRoot->left)&&IsBalanced_Solution(pRoot->right);  //所有对应的子树都是平衡树，才是二叉平衡树
    }
    int TreeDepth(TreeNode* pRoot)
    {
        if(pRoot == NULL)
            return 0;
        int left,right;
        if(pRoot->left==NULL)
            left = 0x80000000;
        if(pRoot->right==NULL)
            right = 0x80000000;
        left = TreeDepth(pRoot->left);
        right = TreeDepth(pRoot->right);
        return left > right ? left + 1 : right + 1;
    }
};