Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Follow up: Can you solve it without using extra space? 这个求单链表中的环的起始点是之前那个判断单链表中是否有环的延伸,可参见我之前的一篇文章 (http://www.cnblogs.com/grandyang/p/4137187.html). 还是要设…

Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 这道题是快慢指针的经典应用.只需要设两个指针,一个每次走一步的慢指针和一个每次走两步的快指针,如果链表里有环的话,两个指针最终肯定会相遇.实在是太巧妙了,要是我肯定想不出来.代码如下: C++ 解法: class Solution { public: bool hasCycle…

Given a linked list, determine if it has a cycle in it. ExampleGiven -21->10->4->5, tail connects to node index 1, return true Challenge Follow up:Can you solve it without using extra space? LeetCode上的原题,请参见我之前的博客Linked List Cycle. class Solution…

题目要求 Linked List Cycle Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 如何判断一个单链表中有环? Linked List Cycle II Given a linked list, return the node where the cycle begins. If there is no cycle…

Linked List Cycle Given a linked list, determine if it has a cycle in it. Follow up:Can you solve it without using extra space? Linked List Two Pointers     ''' Created on Nov 13, 2014 @author: ScottGu<gu.kai.66@gmail.com, 150316990@qq.com> ''' # De…

Linked List Cycle Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 说明:两个指针不同步长. /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x)…

2.6 Given a circular linked list, implement an algorithm which returns the node at the beginning of the loop.DEFINITIONCircular linked list: A (corrupt) linked list in which a node's next pointer points to an earlier node, so as to make a loop in the…

Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Follow up: Can you solve it without using extra space? 解题思路,本题和上题十分类似,但是需要观察出一个规律,参考LeetCode:Linked List Cycle II JAVA实现如下: public ListNode detectCycle(Li…

Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Follow up:Can you solve it without using extra space? 思路 这题是Linked List Cycle的进阶版 Given a linked list, determine if it has a cycle in it. bool hasCycle(Li…

今天星期天,准备好周一的PPT内容,再回来做题,以后考虑周末做一个APP或者微信帐号玩吧. 回到题目, Linked List Cycle,一个检查单项链表是否有环路的问题. 题目周五的时候就简单做过,可是链表中带入了一个val常量,当时误以为是要检查是否有重复值,WA了. 早上再试了会,缓过来,其实还是比较地址指针. 最开始写的一个简单方法,只能判断是否与头指针重复,但是如果环路从中间开始就判断不到了,再想了10多分钟,有一个O(n^2)的算法,每次从第一个指针开始,判断后面k-1个指针是否相…