Design Parking Lot (OOD)

Problem Overview

Design a parking lot system with these core operations:

• park(vehicle)
• unpark(license_plate)
• check_car(license_plate)

The main constraint is the spot compatibility rule:

• a MOTORCYCLE spot can only be occupied by a MOTORCYCLE vehicle.
• a CAR spot can be occupied by any type of vehicle.

Constraints

1. The parking lot has a fixed number of spots.
2. Each spot can only accommodate one vehicle at a time.
3. The parking lot has a mix of MOTORCYCLE and CAR spots.
4. A MOTORCYCLE vehicle can park in either a MOTORCYCLE or CAR spot.
5. A CAR vehicle can only park in a CAR spot.
6. The parking lot should handle the parking and un-parking of vehicles efficiently.

Examples

1. When a MOTORCYCLE vehicle arrives, it should be parked in the first available MOTORCYCLE spot. If no MOTORCYCLE spot is available, it should be parked in the first available CAR spot.
2. When a CAR vehicle arrives, it should be parked in the first available CAR spot.
3. If a vehicle is unparked, the spot should be marked as available for the next vehicle.

Hints

1. Consider using a data structure to keep track of the available spots and their types.
2. Implement a method to find the first available spot of a specific type.
3. Consider thread safety if the parking lot system is accessed concurrently.

Solution

Here's a possible solution outline for the Design Parking Lot problem:

1. Define a Spot class with properties like spot_type (MOTORCYCLE or CAR) and is_occupied.
2. Define a ParkingLot class with a list of Spot objects and methods like park(vehicle), unpark(license_plate), and check_car(license_plate).
3. In the park(vehicle) method, find the first available spot that matches the vehicle type and mark it as occupied.
4. In the unpark(license_plate) method, find the spot with the given license plate, mark it as unoccupied, and update the vehicle's state.
5. In the check_car(license_plate) method, find the spot with the given license plate and return its state (parked or not).

`python class Spot: def init(self, spot_type): self.spot_type = spot_type self.is_occupied = False

class ParkingLot: def init(self, num_motorcycle_spots, num_car_spots): self.spots = [Spot("MOTORCYCLE") for _ in range(num_motorcycle_spots)] + [Spot("CAR") for _ in range(num_car_spots)]

def park(self, vehicle):
    # Find the first available spot that matches the vehicle type and mark it as occupied
    pass

def unpark(self, license_plate):
    # Find the spot with the given license plate, mark it as unoccupied, and update the vehicle's state
    pass

def check_car(self, license_plate):
    # Find the spot with the given license_plate and return its state (parked or not)
    pass

`

This is a high-level solution outline. You can implement the specific logic for each method based on the problem requirements and constraints.