两个链表的第一个公共节点

这道题目我之前做过就不多解释了：https://www.cnblogs.com/cstdio1/p/13072712.html

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
        ListNode l1=headA,l2=headB;
        while(l1!=l2){
            l1=l1==null? headB:l1.next;
            l2=l2==null? headA:l2.next;
        }
        return l1;

    }
}