import java.util.*; /* public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; } }*/ public class Solution { public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2) { ListNode cur = pHead1; Set<ListNode> set = new HashSet<>(); while(cur!=null){ set.add(cur); cur = cur.next; } cur = pHead2; ListNode target = null; while(cur!=null){ if(set.contains(cur)){ target = cur; break; } cur = cur.next; } return target; } }