AtoB: Design a Parking lot that can handle multiple vehicle types based on certain rules

ParkingLot.py

# # Design a parking lot

# # Assumptions:
# # - The parking lot can hold motorcycles, cars and vans.
# # - The parking lot has spots of 3 sizes: small spots, medium spots and large
# #   spots.
# # - A motorcycle can park in any spot.  A car can park in a single medium spot,
# #   or a large spot.
# # - A van can park, but it will take up 3 medium spots or a large spot. For the
# #   purposes of this exercise, don’t worry about if the medium spots are next to
# #   each other.
# # - These are just a few assumptions. Feel free to ask your interviewer about
# #   more assumptions as needed.

# # Please implement a parking lot with following functionality:
# # - The ability to park a vehicle in the parking lot.
# # - The ability to remove (unpark) a vehicle that has been previously parked.


class ParkingLot:
    
    VEHICLE_PARKING_RULES = {
        "MOTORCYCLE": [("SMALL", 1), ("MEDIUM", 1), ("LARGE", 1)],
        "CAR": [("MEDIUM", 1), ("LARGE", 1)],
        "VAN": [("LARGE", 1), ("MEDIUM", 3)]
    }

    def __init__(self, small_spots, medium_spots, large_spots):
        self.TOTAL_SPOT_CAPACITIES = {"SMALL": small_spots, "MEDIUM": medium_spots, "LARGE" : large_spots}

        self.current_occupancy = {}

    def park(self, vehicle_type, vin):
        if vin in self.current_occupancy:
            return False
         
        for rule in self.VEHICLE_PARKING_RULES[vehicle_type]:
            # spot_type, spot_taken_amount = rule
            if self.TOTAL_SPOT_CAPACITIES[rule[0]] >= rule[1]:
                self.TOTAL_SPOT_CAPACITIES[rule[0]] = self.TOTAL_SPOT_CAPACITIES[rule[0]] - rule[1]
                self.current_occupancy[vin] = (rule[0], rule[1])
                return True

        return False

    def unpark(self, vin):
        if vin not in self.current_occupancy:
            return False

        vehicle_type = self.current_occupancy[vin][0]
        vehicle_spots_taken = self.current_occupancy[vin][1]

        self.TOTAL_SPOT_CAPACITIES[vehicle_type] = self.TOTAL_SPOT_CAPACITIES[vehicle_type] + vehicle_spots_taken
        del self.current_occupancy[vin]

        return True

    def pretty_print(self):
        return self.TOTAL_SPOT_CAPACITIES
        


# 1s, 4m, 1l

# park moto -> 1s
# park car -> 1m
# park van1 -> 1l
# park van2 -> 3m
# unpark van1 -> 1l cleared up

# pl = ParkingLot(1, 4, 1)
# print(pl.pretty_print())
# print(pl.park("MOTORCYCLE", "M1"))
# print(pl.pretty_print())
# print(pl.park("CAR", "C1"))
# print(pl.pretty_print())
# print(pl.park("VAN", "VAN1"))
# print(pl.pretty_print())
# print(pl.park("VAN", "VAN2"))
# print(pl.pretty_print())
# print(pl.unpark("VAN1"))
# print(pl.pretty_print())
# print(pl.park("VAN", "VAN3"))
# print(pl.pretty_print())
# print(pl.park("MOTORCYCLE", "M2"))
# print(pl.pretty_print())


pl2 = ParkingLot(0, 1, 4)
print(pl2.pretty_print())
print(pl2.park("MOTORCYCLE", "M1"))
print(pl2.pretty_print())
print(pl2.park("MOTORCYCLE", "M2"))
print(pl2.pretty_print())
print(pl2.park("CAR", "C1"))
print(pl2.pretty_print())
print(pl2.unpark("C2"))
print(pl2.pretty_print())
print(pl2.park("CAR", "C1"))
print(pl2.pretty_print())