题解 | #配置文件恢复#

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] list = {"reset","board","reboot","backplane"};
		
		while(sc.hasNextLine()){
			Scanner scanLine = new Scanner(sc.nextLine());
			if(scanLine.hasNext()){
				String str1 = scanLine.next();
				
				int cmd1 = 0;
				String cmd2 = "null";
				
				if(scanLine.hasNext()){
					cmd2 = scanLine.next();
					
					int cmd1Count = 0;
					for(int i=1; i<=4; i++){
						if(list[i-1].startsWith(str1)){
							cmd1Count++;
							cmd1 = i;
						}
					}
					
					if(cmd1Count == 1){
						switch(cmd1){
							case 1:{
								if("board".startsWith(cmd2)){
									System.out.println("board fault");
								}else{
									System.out.println("unknown command");
								}
							}break;
							
							case 2:{
								
								if("add".startsWith(cmd2)){
									System.out.println("where to add");
								}else if("delete".startsWith(cmd2)){
									System.out.println("no board at all");
								}else{
									System.out.println("unknown command");
								}
							}break;
							
							case 3:{
								
								if("backplane".startsWith(cmd2)){
									System.out.println("impossible");
								}else{
									System.out.println("unknown command");
								}
								
							}break;
							
							case 4:{
								
								if("abort".startsWith(cmd2)){
									System.out.println("install first");
								}else{
									System.out.println("unknown command");
								}
							}break;
							
						}
					}else{
						System.out.println("unknown command");
					}
				}else{
					if("reset".startsWith(str1)){
						System.out.println("reset what");
					}else{
						System.out.println("unknown command");
					}
				}
			}
			scanLine.close();
		}
		sc.close();
	}
}