LeetCode141:Linked List Cycle】的更多相关文章

题目: Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 解题思路: 判断链表有无环,可用快慢指针进行,快指针每次走两步,慢指针每次走一步,如果快指针追上了慢指针,则存在环,否则,快指针走到链表末尾即为NULL是也没追上,则无环. 为什么快慢指针可以判断有无环? 因为快指针先进入环,在慢指针进入之后,如果把慢指针看作在前面,快…
1.Linked List Cycle 题目链接 题目要求: Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 刚看到这道题,很容易写出下边的程序: bool hasCycle(ListNode *head) { ListNode *a = head, *b = head; while(a) { b = a->next; wh…
题目: 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: 判断链表有无环,可用快慢指针进行,快指针每次走两步,慢指针每次走一步,如果快指针追上了慢指针,则存在环,否则,快指针走到链表末尾即为NULL是也没追上,则无环. 为什么快慢指针可…
Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Note: Do not modify the linked list. Follow up:Can you solve it without using extra space? 和前面那题类似,只不过这里要找到的是环开始的节点,看下面这张图(图是盗的): 当fast以及slow指针在z处相遇的时候,可以…
Given a linked list, determine if it has a cycle in it. Follow up:Can you solve it without using extra space? 判断一个链表是否存在环,维护快慢指针就可以,如果有环那么快指针一定会追上慢指针,代码如下: class Solution { public: bool hasCycle(ListNode *head) { ListNode * slow, * fast; slow = fast…
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, return the node where the cycle begins. If there is no cycle, return null. To represent a cycle in the given linked list, we use an integer pos which represents the position (0-indexed) in the linked list where tail connects to.…
Given a linked list, determine if it has a cycle in it. To represent a cycle in the given linked list, we use an integer pos which represents the position (0-indexed) in the linked list where tail connects to. If pos is -1, then there is no cycle in…
链表相关题 141. 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? (Easy) 分析: 采用快慢指针,一个走两步,一个走一步,快得能追上慢的说明有环,走到nullptr还没有相遇说明没有环. 代码: /** * Definition for singly-linked list. * s…