LeetCode 19 Remove Nth Node From End of List (移除距离尾节点为n的节点)

package leetcode_50;

/***
*
* @author pengfei_zheng
*    移除距离尾节点为n的节点
*/
public class Solution19 {

public class ListNode {
int val;
ListNode next;
ListNode(int x) { val = x; }
}
public ListNode removeNthFromEnd(ListNode head, int n) {
if (head.next == null) {
return null;
}
int counter = 1;
ListNode start = new ListNode(0);
start.next = head;//保存头指针
ListNode fast = start;
ListNode slow = start;
while (fast.next != null) {//循环体
fast = fast.next;//快指针移动
if (counter <= n) {
counter++;//计数器
} else {
slow = slow.next;//慢指针移动
}
}
slow.next = slow.next.next;//移除
return start.next;
}
}