[Leetcode] (Python): 101 symmetric tree

Source of the topic

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

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

Test instructions Analysis

Input: a binary tree

Output:true or False

Conditions: Judging If a binary tree is symmetrical

Topic ideas

One by one to determine whether the value is equal, attention should be clear who corresponds to WHO.

AC Code (PYTHON)

1 #Definition for a binary tree node.2 #class TreeNode (object):3 #def __init__ (self, x):4 #self.val = x5 #self.left = None6 #self.right = None7 8 classsolution (object):9     defissymmetric (self, root):Ten         """ One : Type Root:treenode A : Rtype:bool -         """ -         defHelp (P, q): the             ifp = = None andQ = =None: -                 returnTrue -             ifP andQ andP.val = =Q.val: -                 returnHelp (P.left, Q.right) andHelp (P.right, Q.left) +             returnFalse -          +         ifRoot: A             returnHelp (Root.left, Root.right) at         returnTrue -         

[Leetcode] (Python): 101 symmetric tree