Remove Nth Node From End of List

Given a linked list, remove the nth node from the end of list and return its head.

For example,

   Given linked list: 1->2->3->4->5, and n = 2.



   After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:
Given n will always be valid.
Try to do this in one pass.

 

第三遍：

 1 /**

 2  * Definition for singly-linked list.

 3  * public class ListNode {

 4  *     int val;

 5  *     ListNode next;

 6  *     ListNode(int x) {

 7  *         val = x;

 8  *         next = null;

 9  *     }

10  * }

11  */

12 public class Solution {

13     public ListNode removeNthFromEnd(ListNode head, int n) {

14         ListNode header = new ListNode(-1);

15         header.next = head;

16         ListNode fast = header, cur = header, lazy = header;

17         for(int i = 0; i < n; i ++)

18             fast = fast.next;

19             

20         while(fast != null){

21             fast = fast.next;

22             lazy = cur;

23             cur = cur.next;

24         }

25         lazy.next = cur.next;

26         return header.next;

27     }

28 }