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? 思考:第一步:设环长为len,快慢指针q.p相遇时,q比p多走了k*len. 第二部:p先走k*len步,p,q一起走每次一步,相遇时p比q多走了一个环距离,此时q就是环开始结点. 通…
Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 思考:快慢指针,快指针一次走两步,慢指针一次一步.若快指针跟慢指针指向同一个结点,则有环.若快指针到达链表末尾即指向NULL,说明没有环. /** * Definition for singly-linked list. * struct ListNode { * int va…
Linked List Cycle II 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? 和问题一Linked List Cycle几乎一样.如果用我的之前的解法的话,可以很小修改就可以实现这道算法了.但是如果问题一用优化了的解法的话,那么就不适…
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…
问题描述如下: 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? 从问题来看,如果可以充分利用额外空间的话,这个题目是不难的,然而题目提出了一个要求,能否在不使用任何额外空间的情况下解决这个问题. 通过反复思考,我觉得这题类似于追击问题,可以用一个…
Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 原题链接:https://oj.leetcode.com/problems/linked-list-cycle/ 题目:给定一个链表.推断它是否有环. 继续: 你能不用额外的空间解决吗? 思路:使用两个指针fast,slow,fast每次向前走两步,slow每次向前走一步.假设…
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? 原题链接:https://oj.leetcode.com/problems/linked-list-cycle-ii/ 题目:给定一个链表.返回环開始的节点.如无环.返回null. public L…
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? 错误解法.因为Cycle可能出现在Link的中间的,所以需要检查其中间Nodes. bool hasCycle(ListNode *head) { // IMPORTANT: Please reset any member data you…
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…
