Given a linked list, return the node where the cycle begins. If there is no cycle, returnnull. Follow up: 思路: 1)同linked-list-cycle-i一题,使用快慢指针方法,判定是否存在环,并记录两指针相遇位置(Z): 2)将两指针分别放在链表头(X)和相遇位置(Z),并改为相同速度推进,则两指针在环开始位置相遇(Y). 证明如下: 如下图所示,X,Y,Z分别为链表起始位置,环开始位…

/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode *detectCycle(ListNode *head) { ListNode *p1, *p2; //p1和p2从链表的第一个节点出发,p1每次移动一…

Total Accepted: 84303 Total Submissions: 302714 Difficulty: Easy Given a linked list, remove the nth node from the end of list and return its head. For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from t…

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…

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…

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? 参考http://www.cnblogs.com/hiddenfox/p/3408931.html 方法: 第一次相遇时slo…

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: 做过,就当复习了. 先用快慢指针判断相交,关键是环开始点的获取. 用上图说明一下,设非环的部分长度为a(包括环的入口点), 环的长度为b(包括环的入口点). 快慢指针相交的位置为绿色的点,距离…

题目: 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? 给定一个链表的头指针,问你能不能只用常数的空间快速判断一个链表是不是有环,如果有环,返回环的起始位置. 代码: 不能…

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? 借用博客http://www.cnblogs.com/hiddenfox/p/3408931.html的图 设环的距离为L = (b+c),无环的距离为a, 假设在时间t相遇,慢指针行驶距离为x,则…

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)…