题解 | #配置文件恢复#

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);
        String[] first = {"reset", "reset", "board", "board", "reboot", "backplane"};
        String[] second = {"reset what", "board board fault", "add where to add", "delete no board at all", "backplane impossible", "abort install first"};
        while (in.hasNext()) {
            String str = in.nextLine();

            if (!str.contains(" ")) {
                //单字符命令就一个，这里取巧直接输出
                if (first[0].startsWith(str)) {
                    System.out.println(second[0]);
                } else {
                    System.out.println("unknown command");
                }

            } else {
                //输入两字串，遍历两数组，共用同一个索引
                String[] opStr = str.split(" ");
                int count = 0;
                int index = 0;
                for (int i = 0; i < first.length; i++) {
                    if (first[i].startsWith(opStr[0]) && second[i].startsWith(opStr[1])) {
                        count++;
                        index = i;
                        //记录匹配的次数和索引
                    }
                }

                if (count == 1) {
                    int spaceBegin = second[index].indexOf(" ", 0);
                    //找到第一个空格的位置，输出之后的子串
                    System.out.println(second[index].substring(spaceBegin + 1));
                } else {
                    System.out.println("unknown command");
                }

            }
        }
    }
}