题目: Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \ 3 4 4 3 But the following is not: 1 / \ 2 2 \ \ 3 3 Note:Bonus points if you could solve…

给定一个二叉树,检查它是否是镜像对称的. 例如,二叉树 [1,2,2,3,4,4,3] 是对称的. 1 / \ 2 2 / \ / \ 3 4 4 3 但是下面这个 [1,2,2,null,3,null,3] 则不是镜像对称的: 1 / \ 2 2 \ \ 3 3 说明: 如果你可以运用递归和迭代两种方法解决这个问题,会很加分. 考察 1.树的前序遍历 2.如果树的对称前序遍历和树的前序遍历序列一样的,就是对称的二叉树 递归  时间复杂度:O(n).因为我们遍历整个输入树一次,所以总的运行时间为…

题目链接:Symmetric Tree | LeetCode OJ Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \ 3 4 4 3 But the following is not: 1 / \ 2 2 \ \ 3 3 Note: B…

Symmetric Tree Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \ 3 4 4 3 But the following is not: 1 / \ 2 2 \ \ 3 3 Note:Bonus points if you c…

Same Tree Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. 思想: 无.能遍历即可. /** * Definition for binary tree * struct T…

题目:Symmetric Tree <span style="font-size:18px;"><span style="font-size:18px;">/**LeetCode Symmetric Tree 对称的树 * 思路:推断一棵树是否对称,1.有左子树就要有右子树 * 2.除根节点外对称节点值要同样 * 注意:对称后就是左子树的左节点和右子树的右节点比較 * Definition for binary tree * public c…

Symmetric Tree 题目链接 题目要求: Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \ 3 4 4 3 But the following is not: 1 / \ 2 2 \ \ 3 3 Note: Bonus poi…

Symmetric Tree Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1   / \  2   2 / \ / \3  4 4  3But the following is not:    1   / \  2   2   \   \   3    3Note:…

题目大意 #!/usr/bin/env python # coding=utf-8 # Date: 2018-08-30 """ https://leetcode.com/problems/symmetric-tree/description/ 101. Symmetric Tree Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). Fo…

Symmetric Tree Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \ 3 4 4 3 But the following is not: 1 / \ 2 2 \ \ 3 3 Note:Bonus points if you c…