Key-Value Store Design and Implementation

CodingOpenAILast reported August 2026High Frequency
Reported
28× across candidate reports
First seen
January 2025
Last reported
August 2026
Reported outcome
mixed

Problem Overview

OpenAI coding question, reconstructed from 28 candidate reports (January 2025 to August 2026). Tests: in-memory database or key-value store; serialization and encoding. Candidates reported 3 follow-ups. The write-up includes a Python solution that passes 6 test cases.

  • 3 candidate-reported follow-ups — the probes candidates report being asked, with the trigger for each
  • The full problem statement — full requirements, constraints, and edge cases
  • Approach and trade-offs — what passing candidates did, and the mistakes that sink people
Unlock the full OpenAI catalog
Full problem statements, candidate-reported follow-ups, and walkthroughs — for every OpenAI question.
Unlock with Pro
Already a member? Sign in
Verified Source
Every question is reconstructed from multiple independent candidate reports. Follow-ups candidates reported, not invented ones.
Codex Fact-Checked
Technical claims, formulas, and scale numbers are reviewed against primary sources.
Interviewer Follow-ups
The follow-ups candidates reported, with the trigger that prompts each one — plus the mistakes that sink people.
Is this helpful?