advent_of_code_2021/04/main.cpp

#include <array>
#include <fstream>
#include <iostream>
#include <sstream>
#include <vector>

class Bingo {
public:
    Bingo() = default;
    ~Bingo() = default;

    void addNumberToCard(int number) {
        card[numbers / 5][numbers % 5] = { number, false };
        numbers += 1;
    }

    void checkNumber(int number) {
        if (hasWon()) {
            invalidate();
            return;
        }
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 5; j++) {
                if (card[i][j].first == number) {
                    card[i][j].second = true;
                    checkWin(number);
                    return;
                }
            }
        }
    }

    bool hasWon() {
        return won;
    }

    int getWinningScore() {
        return winning_score;
    }

    void printSelf() {
        std::cout << std::endl;
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 5; j++) {
                if (card[i][j].second) {
                    std::cout << "*";
                }
                std::cout << card[i][j].first << " ";
            }
            std::cout << std::endl;
        }
        std::cout << std::endl;
    }

    bool isValid() {
        return valid;
    }

private:
    void checkWin(int multiplier) {
        for (int i = 0; i < 5; i++) {
            int horizontal = 0;
            int vertical = 0;
            for (int j = 0; j < 5; j++) {
                if (card[i][j].second) {
                    horizontal += 1;
                }
                if (card[j][i].second) {
                    vertical += 1;
                }
            }
            if (horizontal == 5 || vertical == 5) {
                won = true;
                calculateScore(multiplier);
            }
        }
    }

    void calculateScore(int multiplier) {
        int score = 0;
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 5; j++) {
                if (!card[i][j].second) {
                    score += card[i][j].first;
                }
            }
        }
        winning_score = score * multiplier;
    }

    void invalidate() {
        valid = false;
    }

    std::array<std::array<std::pair<int, bool>, 5>, 5> card;
    int numbers = 0;
    bool won = false;
    int winning_score = -1;
    bool valid = true;
};

std::pair<std::vector<int>, std::vector<Bingo>>
getBingo(const std::string &file_name) {
    std::pair<std::vector<int>, std::vector<Bingo>> result;

    std::ifstream file(file_name);
    int tmp{};
    char tmp_char{};
    std::string str;
    std::getline(file, str);
    std::stringstream ss(str);
    while (ss >> tmp) {
        result.first.push_back(tmp);
        ss >> tmp_char;
    }
    while (std::getline(file, str)) {
        if (str.empty()) {
            result.second.emplace_back();
            continue;
        }
        std::stringstream ss2(str);
        for (int i = 0; i < 5; i++) {
            ss2 >> tmp;
            result.second.back().addNumberToCard(tmp);
        }
    }
    return result;
}

int part1(const std::vector<int> &numbers, std::vector<Bingo> &bingo) {
    for (auto &number : numbers) {
        for (auto &card : bingo) {
            card.checkNumber(number);
            if (card.hasWon()) {
                return card.getWinningScore();
            }
        }
    }
    return -1;
}

int part2(const std::vector<int> &numbers, std::vector<Bingo> &bingo) {
    int last_score = -1;
    for (auto &number : numbers) {
        for (auto &card : bingo) {
            card.checkNumber(number);
            if (card.hasWon() && card.isValid()) {
                last_score = card.getWinningScore();
            }
        }
    }
    return last_score;
}

int main(int argc, char **argv) {
    if (argc < 2) {
        std::cerr << "You must provide input file!" << std::endl;
        return 1;
    }
    auto input = getBingo(argv[1]);
    auto &numbers = input.first;
    auto &bingo = input.second;
    std::cout << "The winning score of the first winning card is \033[91;1m"
              << part1(numbers, bingo) << "\033[0m." << std::endl;
    std::cout << "The winning score of the last winning card is \033[91;1m"
              << part2(numbers, bingo) << "\033[0m." << std::endl;
    return 0;
}