Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space? 这道题让我们判断一个链表是否为回文链表,LeetCode中关于回文串的题共有六道,除了这道,其他的五道为Palindrome Number 验证回文数字,Validate Palindrome 验证回文字符串,Palindrome Partitioning 拆分回文…

Given a singly linked list, determine if it is a palindrome. Follow up:Could you do it in O(n) time and O(1) space? 题目意思: 给定一个单链表,判断它是不是回文串 进一步思考: 你可以在O(n)时间复杂度和O(1)空间复杂度完成吗? 解题思路: 方法一:通过反转链表实现 (1)使用快慢指针寻找链表中点 (2)将链表的后半部分就地逆置 (3)比较前后两半的元素是否一致 (4)恢复原始…

Description: Given a singly linked list, determine if it is a palindrome. Follow up:Could you do it in O(n) time and O(1) space? 判断一个单向链表是不是回文. 思路: 最简单的思路就是,用一个遍历一遍,存下来,再遍历反着做比较.时间复杂度O(n),空间复杂度O(n).竟然能过...... /** * Definition for singly-linked list.…

9 - Palindrome Number Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using extra…

234. Palindrome Linked List 1. 使用快慢指针找中点的原理是fast和slow两个指针,每次快指针走两步,慢指针走一步,等快指针走完时,慢指针的位置就是中点.如果是偶数个数,正好是一半一半,如果是奇数个数,慢指针正好在中间位置,判断回文的时候不需要比较该位置数据. 注意好好理解快慢指针的算法原理及应用. 2. 每次慢指针走一步,都把值存入栈中,等到达中点时,链表的前半段都存入栈中了,由于栈的后进先出的性质,就可以和后半段链表按照回文对应的顺序比较. solution…

Palindrome Linked List Given a singly linked list, determine if it is a palindrome. Follow up:Could you do it in O(n) time and O(1) space? 解法一: 一次遍历,装入vector,然后再一次遍历判断回文. 时间复杂度O(n),空间复杂度O(n) /** * Definition for singly-linked list. * struct ListNode…

Question 234. Palindrome Linked List Solution 题目大意:给一个链表,判断是该链表中的元素组成的串是否回文 思路:遍历链表添加到一个list中,再遍历list的一半判断对称元素是否相等,注意一点list中的元素是Integer在做比较的时候要用equals,因为int在[-128,127)之间在内存中是存储在运行时常量池中,超出这个范围作为对象存储在堆中,==比较的是字面值和对象地址 Java实现: public boolean isPalindrom…

Reverse a singly linked list. click to show more hints. Hint: A linked list can be reversed either iteratively or recursively. Could you implement both? 之前做到Reverse Linked List II 倒置链表之二的时候我还纳闷怎么只有二没有一呢,原来真是忘了啊,现在才加上,这道题跟之前那道比起来简单不少,题目为了增加些许难度,让我们分别用…

Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using ext…

2.7 Implement a function to check if a linked list is a palindrome. LeetCode上的原题,参见我之前的博客Palindrome Linked List 回文链表.…