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?
一个+1 一个+2 看看能不能相遇。注意代码不要写乱了...以后尽量用p1 p2 这种变量名,不要用p ,q让人看着眼花缭乱
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: bool hasCycle(ListNode *head) { ListNode * p1 = head; ListNode * p2 = head; while (p2 != nullptr && p2->next!=nullptr) { p1 = p1->next; p2 = p2->next->next; if (p1 == p2) { return true; } } return false; } };
原文地址:http://www.cnblogs.com/pk28/
与有肝胆人共事,从无字句处读书。
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