NC4 判断链表中是否有环

传送门

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

标签：slow,ListNode,val,NC4,fast,next,链表,有环,return
来源： https://www.cnblogs.com/sxrekord/p/determine_whether_there_are_links_in_the_linked_list.ht