Given a binary tree, check if it is mirror symmetric.

# Definition for a binary tree node. # class TreeNode(object): # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution(object): def isSymmetric(self, root): """ :type root: TreeNode :rtype: bool """ if root==None: return True if self.panduan(root,root) == False: return False return True def panduan(self,a,b): try: print a.left.val,b.right.val,'------' if a.left.val == b.right.val: if self.panduan(a.left,b.right) == False: return False else: return False except: if a.left ! = b.right: return False else: print 'a.left/b.right = none' try: print a.right.val,b.left.val,'------' if a.right.val == b.left.val: if self.panduan(a.right,b.left) == False: return False else: return False except: if a.right ! = b.left: return False else: print 'a.right/b.left = none'Copy the code