Balanced Binary Tree

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace LeetCode
 8 {
 9     class BalancedBT
10     {
11         public bool IsBalanced(TreeNode root)
12         {
13             if (root == null)
14                 return true;
15             //判断左右子树高度差是否大于1
16             if (Math.Abs(Depth(root.left) - Depth(root.right)) > 1)
17                 return false;
18             //递归检查子树
19             return IsBalanced(root.left) && IsBalanced(root.right);
20         }
21 
22         //递归计算,返回树的高度
23         int Depth(TreeNode node)
24         {
25             if (node == null)
26                 return 0;
27             return 1 + Math.Max(Depth(node.left), Depth(node.right));
28         }
29     }
30 }