题解 | #配置文件恢复#

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) {
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        String[] commands = new String[] {"reset", "reset board", "board add", "board delete", "reboot backplane", "backplane abort", "he he"};
        String[] implts = new String[] {"reset what", "board fault", "where to add", "no board at all", "impossible", "install first", "unknown command"};
        int[] indArr = new int[] {0, 6, 6, 6, 7, 10};
        String a, console = "";
        char[] chs;
        char[] comd;
        int i, j, l, cnt, index, lc, match, matchInx;
        boolean invalid;
        try {
            while ((a = r.readLine()) != null && !a.isEmpty()) {
                chs = a.toCharArray();
                l = chs.length;
                i = 0;
                cnt = 1;
                index = 0;
                while (i < l) {
                    if (chs[i] == ' ') {
                        if (i + 1 < l && chs[i + 1] != ' ') index = i + 1;
                        cnt++;
                    }
                    i++;
                }
                if (cnt == 1) {
                    invalid = false;
                    comd = commands[0].toCharArray();
                    if (l > comd.length) {
                        console = console + implts[6] + "\n";
                        continue;
                    }
                    i = 0;
                    while (i < l) {
                        if (chs[i] != comd[i]) {
                            invalid = true;
                            break;
                        }
                        i++;
                    }
                    if (invalid) console = console + implts[6] + "\n";
                    else console = console + implts[0] + "\n";
                    continue;
                }
                if (cnt > 2) {
                    console = console + implts[6] + "\n";
                    continue;
                }
                i = 1;
                match = 0;//匹配的数量
                matchInx = 6;//匹配的索引
                while (i < 6) {
                    invalid = false;//由于遍历时，一个新的命令开始时，判断重新开始，因此invalid初始为false
                    comd = commands[i].toCharArray();
                    lc = comd.length;
                    if (index > indArr[i] || l - index > lc - indArr[i]) {//不匹配
                        i++;
                        continue;
                    }
                    j = 0;
                    while (j < index - 1) {//第一个单词是否匹配
                        if (chs[j] != comd[j]) {
                            invalid = true;
                            break;
                        }
                        j++;
                    }
                    j = 0;
                    while (j < l -
                            index) {//第二个单词是否匹配，以输入的字符串长度为准，因此为l-index
                        if (chs[index + j] != comd[indArr[i] + j]) {
                            invalid = true;
                            break;
                        }
                        j++;
                    }
                    if (!invalid) {
                        matchInx = i;//匹配索引赋值
                        match++;//匹配数量自加
                    }
                    i++;
                }
                if (match != 1) console = console + implts[6] + "\n";
                else console = console + implts[matchInx] + "\n";
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        System.out.print(console);
    }
}