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Delivery Payment Ledger

Build a driver payment ledger in three phases: exact delivery costs from hourly rates and start and end times, payouts that never pay a delivery twice, and a 100,000-delivery performance tier.

Practice in Interview Dashboard

1. Problem Statement

Build the delivery payment ledger described in the README in three phases: exact delivery costs from hourly rates, payouts that never pay a delivery twice, and a 100,000-delivery performance tier. Validate the money edge cases with runs and a hand trace, and say when you use the AI assistant and how you check its output.

2. Live Coding Format

Work in the provided coding workspace while explaining your decisions to the live interviewer. Validation may use inline tests, examples, comments, or a verbal walkthrough.

3. Key Focus Areas

  • 1
    Exact money arithmetic
  • 2
    Rounding rules
  • 3
    Settlement correctness
  • 4
    Verification with runs
  • 5
    Performance under load
  • 6
    Assistant output review

4. What Strong Candidates Should Demonstrate

  • Compute money from rates and durations with exact integer arithmetic and one stated rounding rule.
  • Specify payouts so that no delivery is paid twice and paid plus unpaid always equals the total.
  • Find the operations whose cost grows with history and make them fast without changing results.
  • Check assistant suggestions for floating-point and rounding mistakes before applying them.

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Practice this problem in the live coding workspace while the interviewer probes your clarification, implementation, trade-offs, and validation.

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Core Concepts

Hidden because they name the technique, which a real interviewer would not tell you.

Show core concepts
Financial PrecisionRounding RulesSettlement InvariantsPerformance OptimizationAI-Assisted Verification

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