题解 | #配置文件恢复#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 创建命令和执行结果的对应哈希表
        HashMap<String,String> table = new HashMap<String,String>();
        table.put("reset","reset what");
        table.put("reset board","board fault");
        table.put("board add","where to add");
        table.put("board delete","no board at all");
        table.put("reboot backplane","impossible");
        table.put("backplane abort","install first");

        // 创建命令的字符串数组集合：每个元素是一个数组，数组长度为1或2
        Set<String[]> order = new HashSet<String[]>();
        for (String s : table.keySet()) {
            // 先把每一条命令拆分成数组再加到集合中
            order.add(s.split(" "));
        }
        
        while (in.hasNextLine()) {
            String str = in.nextLine();
            // 把输入的字符串变为字符串数组
            String[] inputChange = str.split(" ");
            // 用于匹配的命令
            String[] compitable = null;
            // 记录匹配的命令个数
            int count = 0;

            for (String[] cmpOrder : order) {
                if (inputChange.length == 1) {
                    if (cmpOrder.length == 2) {
                        continue;
                    }else {
                        // 是否以指定前缀开始
                        if (cmpOrder[0].startsWith(inputChange[0])) {
                            count++;
                            compitable = cmpOrder;
                            continue;
                        }
                    }

                }

                if (inputChange.length == 2) {
                    if (cmpOrder.length == 1) {
                        continue;
                    }else {
                        if (cmpOrder[0].startsWith(inputChange[0])) {
                            if (cmpOrder[1].startsWith(inputChange[1])) {
                                count++;
                                compitable = cmpOrder;
                                continue;
                            }
                        }
                    }

                }
            }

            if (compitable == null || count == 2) System.out.println("unknown command");
            else if (compitable.length == 1) System.out.println(table.get(compitable[0]));
            else System.out.println(table.get(compitable[0] + " " + compitable[1]));
            
        }

        in.close();
    }

}