题解 | #判断链表中是否有环#

/**
 * Definition for singly-linked list.
 * class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public boolean hasCycle(ListNode head) {
         if(head == 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;
        
    }
}