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.

 

对每个节点计算该节点的深度，做过左右节点深度相差大于1，false。

1 /** 2  * Definition for a binary tree node. 3  * struct TreeNode { 4  *     int val; 5  *     TreeNode *left; 6  *     TreeNode *right; 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8  * }; 9  */10 class Solution {11 public:12     int depthOfTree(TreeNode* root)13     {14         if(!root) return 0;15         return max(depthOfTree(root->left),depthOfTree(root->right))+1;16     }17     bool isBalanced(TreeNode* root) {18         if(!root) return true;19         if (abs(depthOfTree(root->left)-depthOfTree(root->right))>1) return false;20         bool left = isBalanced(root->left);21         bool right = isBalanced(root->right);22         return left&&right;23     }24 };