NC4 判断链表中是否有环

NC4 判断链表中是否有环

判断链表中是否有环_牛客题霸_牛客网 (nowcoder.com)

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//快慢指针
import java.util.*;
public class Solution {
    public boolean hasCycle(ListNode head) {
        if(head==null||head.next==null){
            return false;
        }
        ListNode slow=head;
        ListNode fast=head;
        while(fast!=null&&fast.next!=null){
            slow=slow.next;
            fast=fast.next.next;
            if(slow==fast){
                return true;
            }
        }
        return false;
    }
}