Java求相交链表编写一个程序，找到两个单链表相交的起始节点。

/**
 * 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 A=headA,B=headB;

        if(A==null||B==null){
            return null;
        }
        while(A!=B){
            A=(A==null?headB:A.next);
            B=(B==null?headA:B.next);
        }
        return A;
    }
}