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 depth(root:TreeNode):
            if root==None:
                return 0
            left = depth(root.left)
            right = depth(root.right)
            return left+1 if left>right else right+1
        if not pRoot:
            return True
        left = depth(pRoot.left)
        right = depth(pRoot.right)
        if abs(left-right)>1:
            return False
        return self.IsBalanced_Solution(pRoot.left) and self.IsBalanced_Solution(pRoot.right)