https://leetcode.com/problems/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?
Accepted
324,757
Submissions
938,662
Seen this question in a real interview before?
代码：
/**
* 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 *slow = head, *fast = head;
while (fast && fast->next) {
slow = slow->next;
fast = fast->next->next;
if (slow == fast) return true;
}
return false;
}
};
快慢指针 如果是个环的话那么快慢指针一定会遇到！ 第一次遇到快慢指针的问题居然是在链表里 毕竟链表我还没看很懂啊