题解 | #配置文件恢复#

#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main() {
    vector<vector<string>> command = {{"reset"}, {"reset", "board"}, {"board", "add"}, {"board", "delete"}, {"reboot", "backplane"}, {"backplane", "abort"}};
    string s;
    while (getline(cin, s)) {
        int n = s.size(), blank_loc = -1, num = 1, out = 0;
        for (int i = 0; i < n; i++) {
            if (s[i] == ' ') {
                blank_loc = i;
                break;
            }
        }
        // 判断本次输入几个字符串num
        if (blank_loc != -1) {
            num = 2;
        }

        if (num == 1) {
            if (n <= command[0][0].size() && s == command[0][0].substr(0, n)) {
                out = 1;
            }
        } else if (num == 2) {
            int tmp = 0;
            int n1 = blank_loc, n2 = n - blank_loc - 1;
            for (int i = 1; i <= 5; i++) {
                if (n1 <= command[i][0].size() &&
                        s.substr(0, n1) == command[i][0].substr(0, n1)) {
                    if (n2 <= command[i][1].size() &&
                            s.substr(blank_loc + 1, n2) == command[i][1].substr(0, n2)) {
                        tmp++;
                        out = i + 1;
                    }
                }
            }
            if (tmp != 1) {
                out = 0;
            }
        }

        switch (out) {
            case 0:
                cout << "unknown command" << endl;
                break;
            case 1:
                cout << "reset what" << endl;
                break;
            case 2:
                cout << "board fault" << endl;
                break;
            case 3:
                cout << "where to add" << endl;
                break;
            case 4:
                cout << "no board at all" << endl;
                break;
            case 5:
                cout << "impossible" << endl;
                break;
            case 6:
                cout << "install first" << endl;
                break;
        }
    }
    return 0;
}
// 64 位输出请用 printf("%lld")

本题难点在于如何完成判断匹配的逻辑，主要通过判断长度和是否相等完成匹配，通过计数完成唯一。