判断是否为平衡二叉树

题目描述

输入一棵二叉树，判断该二叉树是否是平衡二叉树。

 

在这里，我们只需要考虑其平衡性，不需要考虑其是不是排序二叉树

解法1：逐个判断每个节点

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def IsBalanced_Solution(self, pRoot):
        # write code here
        if  not pRoot:
            return True        
        if abs(self.tree(pRoot.left) -self.tree(pRoot.right))>1:
            return False
        return self.IsBalanced_Solution(pRoot.left) and self.IsBalanced_Solution(pRoot.right)
  
    def tree(self,pRoot):
        # 求深度
        if not pRoot:
            return 0
        if not pRoot.left and not pRoot.right:
            return 1
        return max(self.tree(pRoot.left),self.tree(pRoot.right))+1