The parsing part felt fine at first, then the edge cases in the fee rules started stacking up and I realized I'd been skimming the spec instead of actually reading it.
Start by clarifying the fee rules and edge cases, then outline a row-by-row processing pipeline that parses the CSV, applies the rules, and outputs the required fields. Emphasize modularity, error handling, and testability, and discuss trade-offs between simplicity and extensibility.
Pro tip: Mention that you would design the fee rules as a configurable strategy or rule engine so that new payment methods or fee structures can be added without modifying core logic. Also, highlight the importance of validating inputs and handling missing or malformed data gracefully.
Ask questions to fully understand the fee-calculation rules, input CSV format, expected output, and any edge cases (e.g., refunds, currency, rounding).
Outline a modular approach: read CSV, parse each row, apply fee rules based on payment method/type, compute fee, and format output. Consider using a rule engine or strategy pattern for extensibility.
Discuss how to handle missing fields, invalid amounts, unknown payment methods, and rounding. Propose logging and error reporting mechanisms.
Write clean, testable code with unit tests for each fee rule and integration tests for the full pipeline. Use sample data to verify correctness.
Talk about performance considerations for large files, potential for parallel processing, and trade-offs between a simple script and a more complex rule engine.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.