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) {
 
    int length1 = getLengthx(pHead1);
        int length2 = getLengthx(pHead2);

        while (length1 != length2) {
            if (length1 > length2) {
                pHead1 = pHead1.next;
                length1--;
            } else {
                pHead2 = pHead2.next;
                length2--;
            }
        }

        while (pHead1!=pHead2) {
            pHead1 = pHead1.next;
            pHead2 = pHead2.next;
        }

        return pHead1;
    }

    private int getLengthx(ListNode pHead1) {
        int i = 0;
        while(pHead1!=null) {
            pHead1 = pHead1.next ;
            i++;
        }
        return i;
    }
}