题解 | #判断是不是平衡二叉树# #判断是不是平衡二叉树#

#coding:utf-8
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pRoot TreeNode类 
# @return bool布尔型
#
class Solution:
    def IsBalanced_Solution(self , pRoot ):
        # write code here
        #process
        ##corner
        if pRoot == None:
            return True 
        ##common 
        left_max_depth = self.get_max_depth(pRoot.left)
        right_max_depth = self.get_max_depth(pRoot.right)
        if abs(left_max_depth - right_max_depth) > 1:
            return False 
        
        is_balanced_left = self.IsBalanced_Solution(pRoot.left)
        is_balanced_right = self.IsBalanced_Solution(pRoot.right)

        return is_balanced_left and is_balanced_right

    def get_max_depth(self, node):
        if node == None:
            return 0
        left_depth = self.get_max_depth(node.left)
        right_depth = self.get_max_depth(node.right)

        return max(left_depth, right_depth) + 1