The interviewer read the whole thing out loud instead of sharing it on screen, which threw me off more than I expected.
Start by clarifying the problem and constraints, then design a clean OOP model with interfaces and classes that encapsulate the core data structure. Implement the base solution with tests, and for each follow-up constraint, discuss trade-offs and refactor the design to accommodate new requirements without breaking existing code.
Pro tip: Treat follow-up constraints as opportunities to demonstrate extensibility: explicitly state how your design adheres to SOLID principles, and mention that you would write unit tests for each new constraint to ensure correctness.
Ask questions to understand the problem scope, expected operations, performance requirements, and potential follow-up constraints. Confirm assumptions before designing.
Identify key abstractions, define interfaces, and outline class hierarchies. Focus on encapsulation, inheritance, and polymorphism to allow future extensions.
Write clean, modular code for the core data structure and operations. Include basic tests to validate functionality and edge cases.
For each new constraint, analyze impact, propose design changes (e.g., new subclasses, strategy patterns), and discuss trade-offs like time/space complexity and maintainability.
Refactor if needed, ensure code quality, and summarize how the design meets all constraints. Mention potential optimizations and testing strategies.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.