aoc2020/day_4/main.cpp

#include <iostream>
#include <fstream>
#include <vector>
#include <optional>
#include <variant>

class Passport {
    std::optional<uint32_t> birthYear;
    std::optional<uint32_t> issueYear;
    std::optional<uint32_t> expireYear;
    std::optional<float> height;
    std::optional<std::string> hairColour;
    std::optional<std::string> eyeColour;
    std::optional<uint64_t> passportId;
    std::optional<uint64_t> countryId;

public:
    Passport() = default;

    [[nodiscard]] bool isValid() const {
        return birthYear.has_value()
               && issueYear.has_value()
               && expireYear.has_value()
               && height.has_value()
               && hairColour.has_value()
               && eyeColour.has_value()
               && passportId.has_value();
//               && countryId.has_value();
    }

    Passport &withBirthYear(uint32_t year) {
        this->birthYear = year;
        return *this;
    }

    Passport &withIssueYear(uint32_t year) {
        this->issueYear = year;
        return *this;
    }

    Passport &withExpirationYear(uint32_t year) {
        this->expireYear = year;
        return *this;
    }

    Passport &withHeightInCentimeters(uint32_t cm) {
        this->height = (float) cm;
        return *this;
    }

    Passport &withHeightInInches(uint32_t inches) {
        this->height = inches * 2.54f;
        return *this;
    }

    Passport &withHairColour(std::string colour) {
        this->hairColour = colour;
        return *this;
    }

    Passport &withEyeColour(std::string colour) {
        this->eyeColour = colour;
        return *this;
    }

    Passport &withPassportId(uint64_t id) {
        this->passportId = id;
        return *this;
    }

    Passport &withCountryId(uint64_t id) {
        this->countryId = id;
        return *this;
    }
};

std::vector<std::string> getProperties(std::string &line) {
    std::vector<std::string> properties;
    std::string tmp = line;
    size_t end = tmp.find(' ');

    while (end != std::variant_npos) {
        std::string property = tmp.substr(0, end);
        properties.push_back(property);

        tmp = tmp.substr(end + 1);
        end = tmp.find(' ');
    }

    properties.push_back(tmp);

    return properties;
}

bool isValidHairColour(std::string &str) {
    if (str[0] != '#') return false;
    return std::variant_npos == str.find_first_not_of("0123456789abcdefABCDEF", 1);
}

bool isValidEyeColour(std::string &str) {
    if (str == "amb") return true;
    if (str == "blu") return true;
    if (str == "brn") return true;
    if (str == "gry") return true;
    if (str == "grn") return true;
    if (str == "hzl") return true;
    if (str == "oth") return true;
    return false;
}


int main() {
    std::ifstream input{"../input.txt"};
    std::vector<Passport> passports;

    uint32_t p1ValidCount = 0;
    uint32_t p2ValidCount = 0;
    std::string line;
    Passport p1Passport = {};
    Passport p2Passport = {};
    while (std::getline(input, line)) {
        if (line.empty()) {
            if (p1Passport.isValid()) p1ValidCount++;
            if (p2Passport.isValid()) p2ValidCount++;
            p1Passport = {};
            p2Passport = {};
            continue;
        }

        std::vector<std::string> properties = getProperties(line);

        for (std::string &property : properties) {
            std::string type = property.substr(0, 3);
            std::string value = property.substr(4);

            if (type == "byr") {
                try {
                    uint32_t year = std::stoi(value);
                    p1Passport.withBirthYear(year);
                    if (year >= 1920 && year <= 2002) p2Passport.withBirthYear(year);
                } catch (const std::exception &) {
                    std::cout << value << " is not an integer. [BYR]" << std::endl;
                }
            } else if (type == "iyr") {
                try {
                    uint32_t year = std::stoi(value);
                    p1Passport.withIssueYear(year);
                    if (year >= 2010 && year <= 2020) p2Passport.withIssueYear(year);
                } catch (const std::exception &) {
                    std::cout << value << " is not an integer. [IYR]" << std::endl;
                }
            } else if (type == "eyr") {
                try {
                    uint32_t year = std::stoi(value);
                    p1Passport.withExpirationYear(year);
                    if (year >= 2020 && year <= 2030) p2Passport.withExpirationYear(year);
                } catch (const std::exception &) {
                    std::cout << value << " is not an integer. [EYR]" << std::endl;
                }
            } else if (type == "hgt") {
                // Account for whether its inches or centimeters
                std::string unit = value.substr(value.length() - 2);

                if (unit == "in") {
                    try {
                        uint32_t number = std::stoi(value.substr(0, value.length() - 2));
                        p1Passport.withHeightInInches(number);
                        if (number >= 59 && number <= 76) p2Passport.withHeightInInches(number);
                    } catch (const std::exception &) {
                        std::cout << value << " is not an integer. [HGT:cm]" << std::endl;
                    }
                } else if (unit == "cm") {
                    try {
                        uint32_t number = std::stoi(value.substr(0, value.length() - 2));
                        p1Passport.withHeightInCentimeters(number);
                        if (number >= 150 && number <= 193) p2Passport.withHeightInCentimeters(number);
                    } catch (const std::exception &) {
                        std::cout << value << " is not an integer. [HGT:in]" << std::endl;
                    }
                } else {
                    // Assume centimeters. NOTE: This case is invalid in Part 2
                    try {
                        uint32_t number = std::stoi(value);
                        p1Passport.withHeightInCentimeters(number);
                    } catch (const std::exception &) {
                        std::cout << value << " is not an integer. [HGT]" << std::endl;
                    }
                }
            } else if (type == "hcl") {
                p1Passport.withHairColour(value);
                if (isValidHairColour(value)) p2Passport.withHairColour(value);
            } else if (type == "ecl") {
                p1Passport.withEyeColour(value);
                if (isValidEyeColour(value)) p2Passport.withEyeColour(value);
            } else if (type == "pid") {
                try {
                    uint64_t id = std::stoll(value);
                    p1Passport.withPassportId(id);

                    if (value.length() == 9) p2Passport.withPassportId(id);
                } catch (const std::exception &) {
                    std::cout << value << " is not a 64-bit integer. [PID]" << std::endl;
                    p1Passport.withPassportId(0); // NOTE: This is needed to pass part 1.
                }
            } else if (type == "cid") {
                try {
                    uint64_t id = std::stoll(value);
                    p1Passport.withCountryId(id);
                } catch (const std::exception &) {
                    std::cout << value << " is not an 64-bit integer. [CID]" << std::endl;
                }
            }
        }
    }

    // Check for last p1Passport and P2Passport
    if (p1Passport.isValid()) p1ValidCount++;
    if (p2Passport.isValid()) p2ValidCount++;

    std::cout << "(P1) Valid Passports: " << p1ValidCount << std::endl;
    std::cout << "(P2) Valid Passports: " << p2ValidCount << std::endl;

    return 0;
}