题解 | #配置文件恢复#

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] firstCommands=new String[]{"reset","reset","board","board","reboot","backplane"};
        String[] secondCommands=new String[]{"","board","add","delete","backplane","abort"};
        String[] results=new String[]{"reset what\n","board fault\n","where to add\n","no board at all\n","impossible\n","install first\n",};
        String unknown="unknown command\n";
        String str = null;
        StringBuilder sb=new StringBuilder();
        while ((str = br.readLine()) != null) {
            String[] command=str.split(" ");
            //只有一个子串时，只能匹配一个子串的命令reset
            if(command.length==1){
                if(firstCommands[0].contains(str)){
                    sb.append(results[0]);
                }else{
                    sb.append(unknown);
                }
                continue;
            }
            //超过两个子串，不符合逻辑
            if(command.length>2){
                sb.append(unknown);
                continue;
            }
            //两个子串时，需判断是否有多项匹配
            int sum=0;
            String result=null;
            for(int i=1;i<6;i++){
                if(firstCommands[i].startsWith(command[0])&&secondCommands[i].startsWith(command[1])){
                    sum++;
                    result=results[i];
                }
            }
            if(sum==1){
                sb.append(result);
            }else{
                sb.append(unknown);
            }
        }
        System.out.print(sb.toString());
    }
}