题解 | #删除链表的倒数第n个节点#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @param n int整型 
     * @return ListNode类
     */
    public ListNode removeNthFromEnd (ListNode head, int n) {
        // write code here
        ListNode dummyNode = new ListNode(-1);
        dummyNode.next = head;
        ListNode currentNode = dummyNode;
        int size = 0;
        while(currentNode.next != null){
            currentNode = currentNode.next;
            size ++;
        }
        currentNode = dummyNode;
        for(int i = size; i > n; i --){
            currentNode = currentNode.next;
        }
        currentNode.next = currentNode.next.next;
        return dummyNode.next;
    }
}