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.（Easy）
分析：
利用辅助函数求深度，然后根据heighted-balanced定义判定即可
代码：
1 class Solution { 2 int depth(TreeNode* root) { 3 if (root == nullptr) { 4 return 0; 5 } 6 return max(depth(root -> left), depth(root -> right)) + 1; 7 } 8 public: 9 bool isBalanced(TreeNode* root) { 10 if (root == nullptr) { 11 return true; 12 } 13 int left = depth(root -> left); 14 int right = depth(root -> right); 15 if (abs(left - right) <= 1 && isBalanced(root -> left) && isBalanced(root -> right)) { 16 return true; 17 } 18 return false; 19 } 20 };
LeetCode110 Balanced Binary Tree
原文：http://www.cnblogs.com/wangxiaobao/p/6044937.html