leetcode141——Linked List Cycle

题目大意：判断链表中是否有环

分析：快慢指针相遇则有环

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* fast = head;
        ListNode* slow = head;
        while(fast && fast->next){
            fast = fast->next->next;
            slow = slow->next;
            if(slow == fast) return true;
        }
        return false;
    }
};

 

来源：CSDN

作者：tzyshiwolaogongya

链接：https://blog.csdn.net/tzyshiwolaogongya/article/details/104533092