题目

给你一个链表，删除链表的倒数第 n 个结点，并且返回链表的头结点。

示例 1：

输入：head = [1,2,3,4,5], n = 2
输出：[1,2,3,5]

解

class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        ListNode dummy  = new ListNode(0);
        dummy.next = head;
        ListNode slow = dummy;
        ListNode fast = dummy;
        for(int i = 0;i < n;i++){
            fast = fast.next;
        }

        while(fast.next != null){
            slow = slow.next;
            fast = fast.next;
        }

        slow.next = slow.next.next;
        return dummy.next;
    }
}