题目描述：
代码：
1 #include <bits/stdc++.h> 2 using namespace std; 3 class Solution { 4 public: 5 bool isBalanced(TreeNode* root) 6 { 7 int h = 0; 8 return isBalancedHelper(root,h); 9 } 10 11 bool isBalancedHelper(TreeNode* root,int &height) 12 { 13 if(root == nullptr) 14 { 15 height = 0; 16 return true; 17 } 18 int left_h = 0; 19 int right_h = 0; 20 bool left_res = isBalancedHelper(root->left,left_h); 21 bool right_res = isBalancedHelper(root->right,right_h); 22 height = max(left_h,right_h) + 1;//二叉树 root 的高度 23 return left_res && right_res && abs(left_h - right_h) <= 1; 24 } 25 };