题解 | 两个链表的第一个公共结点

import java.util.*;

public class Solution {
    public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2) {
        ListNode pre1 = pHead1;
        ListNode pre2 = pHead2;
        //结束条件是或运算
        //否定中或运算才能保证双重否定，都为null才推出
        while (pre1 != null || pre2 != null) {
            if(pre1 == pre2) return pre1;
            if (pre1 == null) {
                pre1 = pHead2;
            } else {
                pre1 = pre1.next;
            }
            if (pre2 == null) {
                pre2 = pHead1;
            } else {
                pre2 = pre2.next;
            }
        }
        return null;
    }
}