import java.util.HashSet; import java.util.Set; /* 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 a = pHead1; ListNode b = pHead2; while(a != b){ if(a == null){ a = pHead2; }else{ a = a.next; } if(b == null){ b = pHead1; } else { b = b.next; } } return a; } }