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  • [LeetCode]题解(python):101 Symmetric tree

    题目来源


    https://leetcode.com/problems/symmetric-tree/

    Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).


    题意分析


    Input:一个二叉树

    Output:True or False

    Conditions: 判断一个二叉树是不是对称的


    题目思路


    一一对应判断值是否相等,注意要清楚谁对应谁。


    AC代码(Python)

     1 # Definition for a binary tree node.
     2 # class TreeNode(object):
     3 #     def __init__(self, x):
     4 #         self.val = x
     5 #         self.left = None
     6 #         self.right = None
     7 
     8 class Solution(object):
     9     def isSymmetric(self, root):
    10         """
    11         :type root: TreeNode
    12         :rtype: bool
    13         """
    14         def help(p, q):
    15             if p == None and q == None:
    16                 return True
    17             if p and q and p.val == q.val:
    18                 return help(p.left, q.right) and help(p.right, q.left)
    19             return False
    20         
    21         if root:
    22             return help(root.left, root.right)
    23         return True
    24         
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  • 原文地址:https://www.cnblogs.com/loadofleaf/p/5502263.html
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