The twist here is you spend most of the interview just talking.
Clarify requirements first (e.g., scale, payment frequency, delivery types), then propose a modular system with a data model for workers, deliveries, and payments, and algorithms for calculating pay (e.g., per delivery, hourly, bonuses). Discuss trade-offs between batch vs. real-time processing, and how to ensure accuracy and idempotency in distribution.
Pro tip: Emphasize idempotency and auditability in payment distribution—use unique transaction IDs and ledger entries to prevent duplicate payments and enable reconciliation. This shows you understand financial systems' critical requirements.
Ask about scale (number of workers, deliveries per day), payment frequency (daily, weekly), pay structure (per delivery, hourly, tips, bonuses), and regulatory constraints. This ensures the design meets actual needs.
Define entities: Worker, Delivery, Payment, and Ledger. Choose appropriate data structures (e.g., hash maps for worker lookup, queues for pending payments, trees for hierarchical pay rules) and justify choices based on access patterns.
Outline algorithms to compute pay per worker: aggregate deliveries, apply rates, add bonuses/tips, deduct fees/taxes. Discuss handling edge cases like cancelled deliveries, overtime, or multi-currency.
Propose how payments are disbursed: batch processing (e.g., nightly) vs. real-time. Include idempotent operations, retries, and integration with payment gateways. Ensure atomicity and consistency.
Discuss partitioning (e.g., by worker ID), caching, and asynchronous processing. Mention monitoring, alerting, and reconciliation to handle failures and ensure accuracy.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.