/** * Definition for a binary tree node. * public class TreeNode { *     public int val; *     public TreeNode left; *     public TreeNode right; *     public TreeNode(int x) { val = x; } * } */public class Solution {    private int height(TreeNode node)        {            if (node == null)            {                return 0;            }            int lH = height(node.left);            if (lH == -1)            {                return -1;            }            int rH = height(node.right);            if (rH == -1)            {                return -1;            }            if (lH - rH < -1 || lH - rH > 1)            {                return -1;            }            return Math.Max(lH, rH) + 1;        }        public bool IsBalanced(TreeNode root)        {            if (root == null)            {                return true;            }            return height(root) != -1;        }}

 

补充一个python的实现：

1 class Solution: 2     def __init__(self): 3         self.result = True 4          5     def maxDepth(self,root): 6         if root == None: 7             return 0 8         l = self.maxDepth(root.left) 9         r = self.maxDepth(root.right)10         d = max(l,r) + 111         if abs(l - r) > 1:12             self.result = False13         return d14     15     def isBalanced(self, root: TreeNode) -> bool:16         self.maxDepth(root)17         return self.result