题目描述:请实现一个函数,用来判断一颗二叉树是不是对称的。注意,如果一个二叉树同此二叉树的镜像是同样的,定义其为对称的。
Solutions
不要被左子树右子树的禁锢太深。
# -*- coding:utf-8 -*-
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def isSymmetrical(self, pRoot):
# write code here
return self.isSymmetricalCore(pRoot, pRoot)
def isSymmetricalCore(self, pRoot1, pRoot2):
if pRoot1 is None and pRoot2 is None:
return True
if pRoot1 is None or pRoot2 is None:
return False
if pRoot1.val != pRoot2.val:
return False
return self.isSymmetricalCore(pRoot1.left, pRoot2.right) and self.isSymmetricalCore(pRoot1.right, pRoot2.left)
# 运行时间:26ms
# 占用内存:5752k