LeetCode-19删除链表的倒数第N个结点-中等

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。

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

输入：head = [1], n = 1
输出：[]

输入：head = [1,2], n = 1
输出：[1]

链表中结点的数目为 sz1 <= sz <= 300 <= Node.val <= 1001 <= n <= sz 代码Java

public ListNode removeNthFromEnd(ListNode head, int n) {
    ListNode p = head;
    ListNode s = head;
    while (p != null) {
        if (n < 0) {
            s = s.next;
        }
        p = p.next;
        n--;
    }
    if (n == 0)
        return head.next;
    else {
        s.next = s.next.next;
        return head;
    }
}