题解 | #判断链表中是否有环#
判断链表中是否有环
https://www.nowcoder.com/practice/650474f313294468a4ded3ce0f7898b9
import java.util.*; /** * 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; } if (head.val == 100001) { return true; } head.val = 100001; return hasCycle(head.next); } }
遍历链表,走过设置一个不可能存在的值,直到遍历到这个值返回true,遍历到尾返回false
#判断链表是否优化,超简单实现,但总感觉哪里不对#