Спринт 10. Устройство unordered_map и unordered_set. Задание 1.

#include <array>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using namespace std;

class VehiclePlate {
private:
    auto AsTuple() const {
        return tie(letters_, digits_, region_);
    }

public:
    bool operator==(const VehiclePlate& other) const {
        return AsTuple() == other.AsTuple();
    }

    VehiclePlate(char l0, char l1, int digits, char l2, int region) : letters_{l0, l1, l2}
                                                                    , digits_(digits)
                                                                    , region_(region) {}

    string ToString() const {
        ostringstream out;
        out << letters_[0] << letters_[1];
        out << setfill('0') << right << setw(3) << digits_;
        out << letters_[2] << setw(2) << region_;

        return out.str();
    }

    int Hash() const {
        return digits_;
    }

private:
    array<char, 3> letters_;
    int digits_;
    int region_;
};

ostream& operator<<(ostream& out, VehiclePlate plate) {
    out << plate.ToString();
    return out;
}

class VehiclePlateHasher {
public:
    size_t operator()(const VehiclePlate& plate) const {
        return size_t(hash_(plate.ToString()));//
    }
private:
    hash<string> hash_;
};

class ParkingCounter {
public:

    void Park(VehiclePlate car) {
        ++car_to_parks_[car];
    }

    int GetCount(const VehiclePlate& car) const {

        auto helper = car_to_parks_.find(car);

        if (helper == car_to_parks_.end()) {
            return {};
        } else {
            return car_to_parks_.at(car);
        }
    }

    auto& GetAllData() const {
        return car_to_parks_;
    }

private:
    unordered_map<VehiclePlate, int, VehiclePlateHasher> car_to_parks_;
};

int main() {
    ParkingCounter parking;

    parking.Park({'B', 'H', 840, 'E', 99});
    parking.Park({'O', 'K', 942, 'K', 78});
    parking.Park({'O', 'K', 942, 'K', 78});
    parking.Park({'O', 'K', 942, 'K', 78});
    parking.Park({'O', 'K', 942, 'K', 78});
    parking.Park({'H', 'E', 968, 'C', 79});
    parking.Park({'T', 'A', 326, 'X', 83});
    parking.Park({'H', 'H', 831, 'P', 116});
    parking.Park({'A', 'P', 831, 'Y', 99});
    parking.Park({'P', 'M', 884, 'K', 23});
    parking.Park({'O', 'C', 34, 'P', 24});
    parking.Park({'M', 'Y', 831, 'M', 43});
    parking.Park({'B', 'P', 831, 'M', 79});
    parking.Park({'O', 'K', 942, 'K', 78});
    parking.Park({'K', 'T', 478, 'P', 49});
    parking.Park({'X', 'P', 850, 'A', 50});

    assert(parking.GetCount({'O', 'K', 942, 'K', 78}) == 5);
    assert(parking.GetCount({'A', 'B', 111, 'C', 99}) == 0);

    for (const auto& [plate, count] : parking.GetAllData()) {
        cout << plate << " "s << count << endl;
    }
}