题解 | 两个链表的第一个公共结点

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) {
        HashSet<ListNode> set = new HashSet<>();
        ListNode p = pHead1;
        while(p!=null){//将链表1全部存放在hashset中
            set.add(p);
            p = p.next;
        }
        while(pHead2 != null){
            if(set.contains(pHead2)){
                return pHead2;
            }
            pHead2 = pHead2.next;
        }
        return null;
    }
}