题解 | #两个链表的第一个公共结点#

import java.util.HashMap;
import java.util.Map;
/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2) {
        Map<ListNode, Integer> map = new HashMap<>();
        while (pHead1 != null) {
            map.put(pHead1, 1);
            pHead1 = pHead1.next;
        }
        while (pHead2 != null) {
            if (map.containsKey(pHead2)) {
                return pHead2;
            }
            map.put(pHead2, 1);
            pHead2 = pHead2.next;
        }
        return null;
    }
}