题解 | #配置文件恢复#

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

//分情况匹配即可

// 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
        Map<String, String> hashmap = new HashMap<>();
        hashmap.put("reset board", "board fault");
        hashmap.put("board add", "where to add");
        hashmap.put("board delete", "no board at all");
        hashmap.put("reboot backplane", "impossible");
        hashmap.put("backplane abort", "install first");
        while (in.hasNextLine()) {
            String s = in.nextLine();
            String[] ss = s.split(" ");
            if (ss.length > 2) {
                System.out.println("unknown command");
            }
            if (ss.length == 1) {
                if (s.charAt(0) == 'r') {
                    if ("reset".contains(ss[0])) {
                        System.out.println("reset what");
                    }
                    else{
                        System.out.println("unknown command");
                    }
                } else {
                    System.out.println("unknown command");
                }
            }
            if (ss.length == 2) {
                int count = 0;
                String ans = "";
                for (String key : hashmap.keySet()) {
                    String[] keys = key.split(" ");
                    if (keys[0].charAt(0) == ss[0].charAt(0) &&
                            keys[1].charAt(0) == ss[1].charAt(0)) {
                        if (keys[0].contains(ss[0]) && keys[1].contains(ss[1])) {
                            ++count;
                            if (count == 1) {
                                ans = hashmap.get(key);
                            }
                            if (count == 2) {
                                System.out.println("unknown command");
                                break;
                            }
                        }

                    }
                }
                if (count == 1) {
                    System.out.println(ans);
                } else if (count == 0) {
                    System.out.println("unknown command");;
                }
            }

        }
    }
}