题解 |

```import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 
     * @param n int整型 
     * @return ListNode类
     */
    public ListNode removeNthFromEnd (ListNode head, int n) {
        // write code here
        ListNode fast = new ListNode(0);
        ListNode slowRe = new ListNode(0);
        slowRe.next = head;
        ListNode slow = slowRe;
        fast.next = head;
        ListNode pre = slow;
        for (int i = 0; i < n && fast!=null; i++) {
            fast = fast.next;
        }
        while (fast!=null) {
            fast = fast.next;
            pre  = slow;
            slow = slow.next;
        }
        pre.next = slow.next;
        return slowRe.next;
    }
}