LintCode- 链表倒数第n个节点

/**
* Definition for ListNode.
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int val) {
*         this.val = val;
*         this.next = null;
*     }
* }
*/
public class Solution {
/**
* @param head: The first node of linked list.
* @param n: An integer.
* @return: Nth to last node of a singly linked list.
*/
ListNode nthToLast(ListNode head, int n) {
int count = 0;
ListNode re = head;
while(head != null){
count++;
head = head.next;
}
count = count - n;
while(count-- > 0){
re =re.next;
}
return re;
}
}