题解 | #判断是不是平衡二叉树#

# 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: TreeNode) -> bool:
        # write code here
        def dfs(root):
            if not root: return True, 0
            left, left_height = dfs(root.left)
            right, right_height = dfs(root.right)
            if left and right and abs(left_height - right_height) <= 1:
                return True, max(left_height, right_height) + 1
            else:
                return False, -1 
        
        return dfs(pRoot)[0]