Medium

Design a Multi-Floor Parking Lot Object-Oriented Design Interview

Design a parking lot that assigns compatible spots across multiple floors, issues tickets, tracks capacity, and calculates payment when vehicles exit.

1. Problem Statement

Design a multi-floor parking lot that assigns each arriving vehicle a compatible available spot, issues a ticket, tracks capacity, and releases the spot after calculating the fee at exit.

2. Live Coding Format

Work in the provided coding workspace while explaining your decisions to the live interviewer. Validation may use inline tests, examples, comments, or a verbal walkthrough.

3. Key Focus Areas

  • 1
    Vehicle and parking-spot type compatibility
  • 2
    Spot allocation and release
  • 3
    Ticket lifecycle and fee calculation
  • 4
    Capacity display and concurrent allocation

4. What Strong Candidates Should Demonstrate

  • Model vehicles, spots, floors, tickets, and gates with clear ownership.
  • Encapsulate vehicle-to-spot compatibility and occupancy transitions.
  • Separate allocation and pricing policies from parking-lot orchestration.
  • Reason about concurrent entry requests for the last compatible spot.

Want interactive feedback?

Practice this problem in the live coding workspace while the interviewer probes your clarification, implementation, trade-offs, and validation.

Continue to Dashboard

Core Concepts

Object-Oriented DesignAllocation StrategyState Modeling

Continue preparing

Build a complete software engineer mock interview plan

Related Object-Oriented Design

Design a Cricket Information Platform

Design a cricket scoring domain model covering teams and players, a match, innings, overs and deliveries, batting and bowling scorecards, extras and wickets, striker rotation, over completion, and match results for a configurable limited-overs format.

Related Object-Oriented Design

Design a Library Management System

Design a library that models catalog titles versus physical copies, members and librarians, checkout/return/renew/reserve flows with loan due dates, an overdue fine policy, and notifications as a boundary.

Related Object-Oriented Design

Design a Car Rental System

Design a car rental domain model covering vehicle categories and vehicles, branches, customers and drivers, a rental date range, rate-based quotes, reservations, pickup rental agreements, and return inspection with extra charges — preventing overlapping rentals of the same vehicle.

Related Object-Oriented Design

Design a Group Expense-Splitting Ledger

Design a system where users form groups, log shared expenses using pluggable splitting strategies (equal/exact/percentage), maintain pairwise balances, and settle debts.