链表相交

// 链表相交  
// 输入：intersectVal = 8, listA = [4,1,8,4,5], listB = [5,6,1,8,4,5], skipA = 2, skipB = 3  
// 输出：Intersected at '8'  
    public static 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;  
}