题解 | #链表中环的入口结点#
链表中环的入口结点
https://www.nowcoder.com/practice/253d2c59ec3e4bc68da16833f79a38e4
import java.util.*; /* public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; } } */ public class Solution { public ListNode EntryNodeOfLoop(ListNode pHead) { Set<ListNode> s= new HashSet<ListNode>(); while(pHead!=null){ if(s.contains(pHead)){ return pHead; } s.add(pHead); pHead=pHead.next; } return null; } }