删除链表中倒数第n个节点

 1 /**
 2  * Definition for ListNode.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int val) {
 7  *         this.val = val;
 8  *         this.next = null;
 9  *     }
10  * }
11  */ 
12 public class Solution {
13     /**
14      * @param head: The first node of linked list.
15      * @param n: An integer.
16      * @return: The head of linked list.
17      */
18     ListNode removeNthFromEnd(ListNode head, int n) {
19         // write your code here
20         ListNode fast=head;
21         ListNode result = new ListNode(0);
22         result.next = head;
23         for(int i=0;i<n-1;i++){
24             fast = fast.next;
25         }
26         ListNode now = result;
27         while(fast.next != null){
28             fast = fast.next;
29             now = now.next;
30         }
31         now.next = now.next.next;
32         return result.next;
33     }
34 }