Problem Description

Design a parking lot management system, encompassing both software and core components, that supports multiple entry and exit gates, various spot types, ticketing, and payment processing.

Functional Requirements

• Vehicles enter through an entry gate and receive a ticket.
• Vehicles must park in an appropriate available spot (e.g., compact, large, EV, handicap).
• Vehicles exit via an exit gate and pay a fee calculated based on the duration parked, potentially adjusted by vehicle or spot type.
• The system must:
  • Track parking spot occupancy and availability in near real-time.
  • Support parking lots with multiple floors or zones.
  • Handle scenarios such as lost tickets and payment failures gracefully.

Non-Functional Requirements

• Ensure correctness under concurrent arrivals and departures.
• Maintain high availability for all gate operations, allowing ticket issuance and exits even during partial system outages.
• Achieve low latency at gates to prevent long queues.
• Provide auditable records for all payments and occupancy changes.

Deliverables

Candidates are expected to provide:

• A high-level architectural overview.
• The core data model.
• Key APIs.
• Main system flows (e.g., vehicle entry, parking, exit, payment).
• An approach to concurrency and consistency.
• Strategies for failure handling.