Why parking lot is a classic LLD problem - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the basic entity representing a vehicle in the parking lot system.

LLD

class Vehicle:
    def __init__(self, [1]):
        self.license_plate = license_plate

Drag options to blanks, or click blank then click option'

Alicense_plate

Bparking_fee

Centry_time

Dslot_number

Attempts:

3 left

💡 Hint

Common Mistakes

Using slot number as vehicle identifier

Using parking fee as vehicle attribute

The vehicle is identified by its license plate number, which is essential for tracking.

2fill in blank

medium

Complete the code to check if a parking slot is available.

LLD

def is_slot_available(self, [1]):
    return self.slots[slot_id] is None

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Alicense_plate

Bentry_time

Cvehicle

Dslot_id

Attempts:

3 left

💡 Hint

Common Mistakes

Passing vehicle instead of slot ID

Using license plate to check slot availability

We check availability by slot ID, not by vehicle or other attributes.

3fill in blank

hard

Fix the error in the method that assigns a vehicle to a parking slot.

LLD

def park_vehicle(self, vehicle, [1]):
    if self.slots[slot_id] is None:
        self.slots[slot_id] = vehicle
        return True
    return False

Drag options to blanks, or click blank then click option'

Aentry_time

Bslot_number

Cslot_id

Dlicense_plate

Attempts:

3 left

💡 Hint

Common Mistakes

Using slot_number instead of slot_id

Using license_plate as slot key

The parameter name must match the key used to access the slot dictionary, which is slot_id.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps slot IDs to vehicles only if the slot is occupied.

LLD

occupied_slots = { [1]: [2] for [1] in self.slots if self.slots[[1]] is not None }

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Aslot_id

Bvehicle

Cslot_number

Dcar

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for key and loop variable

Using slot_number instead of slot_id

We use slot_id as key and vehicle as value for occupied slots.

5fill in blank

hard

Fill all three blanks to implement a method that calculates total available slots by subtracting occupied slots from total slots.

LLD

def available_slots(self):
    total = len(self.slots)
    occupied = sum(1 for [1] in self.slots if self.slots[[2]] is not None)
    return total - [3]

Drag options to blanks, or click blank then click option'

Aslot_id

Bslot

Coccupied

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for loop and index

Subtracting wrong variable

We iterate over slot_id, check occupancy, and subtract occupied count from total.