You are given several object-oriented coding and design prompts from an onsite loop: a food delivery payment system with methods such as `RecordDelivery`, `PayUpto`, and `AddDelivery`; a rule evaluation engine for expenses with extensible business rules; an article management system with voting and last-flipped-article queries; and a high-level news aggregator similar to Google News. Explain how you would approach these prompts in an interview. <details> <summary>Hint 1</summary> Start by naming the core entities, constraints, and success criteria. </details> <details> <summary>Hint 2</summary> Make the trade-offs explicit before going deep on implementation details. </details> ### Constraints & Assumptions - The focus is clean class design, efficient data structures, and extensibility. - You do not need to write every method, but you should define core APIs and invariants. - The news aggregator part is higher-level system design. - Use the prompt details only; do not assume a full production company stack. ### Clarifying Questions to Ask - What exact method signatures are required? - What does `PayUpto` mean in the payment domain? - How many rules and expenses should the engine support? - What does flipped mean for articles? - Is the news aggregator optimized for freshness, personalization, or publisher coverage? ### What a Strong Answer Covers ```premium-lock What a Strong Answer Covers ``` ### Follow-up Questions - How would you add a new expense rule without changing existing rule code? - How would you make article vote updates efficient? - How would the news aggregator handle duplicate stories? - What would you simplify under a 60-minute coding limit?