设计题

class ParkingSystem {
public:
  ParkingSystem(int big, int medium, int small) {
    this->big = big;
    this->medium = medium;
    this->small = small;
  }

  bool addCar(int carType) {
    switch (carType) {
      case 1:
        if (!big) return false;
        --big;
        break;
      case 2:
        if (!medium) return false;
        --medium;
        break;
      case 3:
        if (!small) return false;
        --small;
        break;
    }
    return true;
  }

private:
  int big, medium, small;

}