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) { List<ListNode> list = new ArrayList<>(); ListNode pNode = new ListNode(0); pNode.next = pHead; while (pNode.next != null) { pNode = pNode.next; if (list.contains(pNode)) { return pNode; } list.add(pNode); } return null; } }