算法: 链表是否重合查询

public class Solution {
    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
         if (headA == null || headB == null){
            return null;
         } 
         ListNode pA = headA, pB = headB;
         while (pA != pB) {
            pA = pA == null ? headB : pA.next;
            pB = pB == null ? headA : pB.next;
         }
         return pA;
    }
}