Leetcode Balanced Binary Tree

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

判断一个二叉树是否为平衡二叉树，主要看左子树和右子树的深度绝对值查是否小于等于1。这里用递归的方法来解决。

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool isBalanced(TreeNode* root) {        if (root == NULL)            return true;        int depthleft = getdepth(root->left,1);        int depthright = getdepth(root->right,1);        if(abs(depthleft-depthright) > 1)        {            return false;        }        else        {            return isBalanced(root->left)&&isBalanced(root->right);        }    }        int getdepth(TreeNode* root,int depth)    {        if(root==NULL)        {            return depth;        }        else        {            return max(getdepth(root->left,depth+1),getdepth(root->right,depth+1));        }    }};