题解 | #两个链表的第一个公共结点#

/*
public class ListNode {
    int val;
    ListNode next = null;

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