160. 相交链表

 public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
        if (headA==null||headB==null){
            return null;
        }

        ListNode startA=headA,startB=headB;
        while (startA!=startB){
            startA=startA==null?headB:startA.next;
            startB=startB==null?headA:startB.next;
        }
        return startA;
    }