19. 删除链表的倒数第 N 个结点

首先先计算出链表的长度,然后得出要删除的节点的索引,然后从前往后遍历到这个索引位置即可/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val val; } * ListNode(int val, ListNode next) { this.val val; this.next next; } * } */ class Solution { public ListNode removeNthFromEnd(ListNode head, int n) { ListNode dummy new ListNode(0); dummy.next head; int length 0; ListNode cur head; while (cur ! null) { length; cur cur.next; } int index length - n; ListNode ptr dummy; while (index 0) { index--; ptr ptr.next; } ptr.next ptr.next.next; return dummy.next; } }