题解 | #输出单向链表中倒数第k个结点#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        // while (in.hasNextInt()) { // 注意 while 处理多个 case
        //     int a = in.nextInt();
        //     int b = in.nextInt();
        //     System.out.println(a + b);
        // }
        while (in.hasNextInt()) {
            int n = in.nextInt();
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = in.nextInt();
            }
            int k = in.nextInt();
            Node head = new Node(arr[0]);
            Node pre = head;
            for (int i = 1; i < n; i++) {
                Node node = new Node(arr[i]);
                pre.next = node;
                pre = node;
            }
            System.out.println(findk(head, k).v);
        }
    }
    private static Node findk (Node head, int k) {
        Node firstNode = head;
        Node secondNode = head;
        int first = 0;

        while (firstNode != null) {
            first++;
            firstNode = firstNode.next;
            if (first > k) {
                secondNode = secondNode.next;
            }
        }
        return secondNode;
    }
}

class Node {
    int v;
    Node next;
    Node (int v) {
        this.v = v;
    }
}