Classic OOD question and I still fumbled the class hierarchy a bit.
Start by clarifying requirements (e.g., multiple floors, vehicle types, payment) and then design a class hierarchy with core entities like ParkingLot, Level, ParkingSpot, and Vehicle. Focus on extensibility and key operations like parking and unparking, discussing trade-offs in data structures and concurrency.
Pro tip: Demonstrate awareness of real-world constraints by discussing how to handle concurrent access to spots and how to scale the design for high throughput, as Uber deals with large-scale systems.
Ask questions to understand scope: number of levels, vehicle types (car, bike, truck), payment methods, entry/exit points, and whether reservations are needed.
Define main classes such as ParkingLot, Level, ParkingSpot, Vehicle, Ticket, and Payment, and their relationships (e.g., ParkingLot has Levels, Level has Spots).
Specify key methods for each class, e.g., ParkingLot.parkVehicle(vehicle), unparkVehicle(ticket), and ParkingSpot.isAvailable(), ensuring separation of concerns.
Detail algorithms for parking (finding an available spot) and unparking (calculating fee), considering data structures like maps or lists for efficient lookup.
Talk about design choices (e.g., spot allocation strategy, concurrency handling) and potential extensions like electric vehicle charging or dynamic pricing.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.