Design an online coding judge
Company: Meta
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Onsite
Design an online coding judge platform where users submit solutions that are compiled and executed against test cases.
Requirements:
- Support multiple languages (e.g., Python, Java, C++).
- Run untrusted code securely with CPU/memory/time limits.
- Asynchronously grade submissions; show status (queued/running/accepted/failed) and results.
- Scale to spikes (contests) and ensure fairness.
Out of scope: full problem authoring UI, plagiarism detection.
Quick Answer: This question evaluates a candidate's understanding of distributed systems, secure execution of untrusted code, resource isolation and limits, asynchronous job processing, multi-language runtime support, and scalability and fairness considerations.