【剑指offer】九，链表中倒数第k个结点

 1 /*
 2 public class ListNode {
 3     int val;
 4     ListNode next = null;
 5  
 6     ListNode(int val) {
 7         this.val = val;
 8     }
 9 }*/
10 public class Solution {
11     public ListNode FindKthToTail(ListNode head,int k) {
12         if(head==null||k==0){
13             return null ;
14         }
15         ListNode p = new ListNode(0) ;
16         ListNode q = new ListNode(0) ;
17         p = head ;
18         q = head ;
19         while(k>1&&p.next!=null){
20             p=p.next ;
21             k-- ;
22         }
23         if(k>=2){
24             return null ;
25         }
26         while(p.next !=null&&q.next!=null){
27             p=p.next ;
28             q=q.next;
29         }
30         return q ; 
31     }
32 }