← Anthropic Interview Insights
The progressive structure is the whole trick.
Start by clarifying the requirements and constraints of the system, then design a clean, extensible architecture that can accommodate future extensions without breaking existing behavior. Implement the core functionality first, and for each extension, ensure backward compatibility by adding new features without modifying existing interfaces or logic.
Pro tip: Emphasize the importance of writing tests for each part before extending, as this ensures that previous behavior remains intact and demonstrates a disciplined engineering approach.
Ask questions to understand the scope, expected operations, and any constraints (e.g., time, space, concurrency). Confirm the incremental nature and that backward compatibility is required.
Sketch a high-level design that separates concerns and uses interfaces or abstract classes to allow future extensions. Consider data structures and algorithms that can be augmented without major refactoring.
Code the initial version with clean, modular code. Write unit tests to verify correctness and establish a baseline for regression testing.
For each new part, add new methods or classes rather than modifying existing ones. Run existing tests to ensure no regressions, and add new tests for the extension.
After all extensions, review the design for any code smells or opportunities to improve maintainability, ensuring all behaviors still work as expected.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.