leetcode110

/**
 * 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 ;
            }
            int lH = height(node.left);
            if (lH == -)
            {
                return -;
            }
            int rH = height(node.right);
            if (rH == -)
            {
                return -;
            }
            if (lH - rH < - || lH - rH > )
            {
                return -;
            }
            return Math.Max(lH, rH) + ;
        }

        public bool IsBalanced(TreeNode root)
        {
            if (root == null)
            {
                return true;
            }
            return height(root) != -;

        }
}

https://leetcode.com/problems/balanced-binary-tree/#/description

补充一个python的实现：

 class Solution:
     def __init__(self):
         self.result = True

     def maxDepth(self,root):
         if root == None:
             return
         l = self.maxDepth(root.left)
         r = self.maxDepth(root.right)
         d = max(l,r) +
         if abs(l - r) > :
             self.result = False
         return d

     def isBalanced(self, root: TreeNode) -> bool:
         self.maxDepth(root)
         return self.result