Competitive Programming Checker — C++ Validator

About OpenTrain

OpenTrain is the #1 platform for people who build careers in AI training and data labeling. We help contributors discover projects, track work across platforms, and grow an AI-training portfolio they control.

We focus on making specialized AI training work easier to find and manage so contributors can build durable freelance careers working on the human side of AI.

About AI Training Work

AI training (often called data labeling, annotation, or human feedback) is the human foundation behind modern AI systems. Contributors prepare and evaluate examples that models learn from — everything from code and text to images, audio, and search relevance.

This role sits at the intersection of software and evaluation: your checker code and validation work directly shape how automated judging treats diverse, valid solutions.

The Role

OpenTrain (hiring via OpenTrain) is looking for a Competitive Programming Checker to design, implement, and run checkers for problems that can have multiple valid outputs. This is a remote contractor position suitable for someone with strong competitive programming experience and advanced C++ skills.

No prior AI experience is required. Prior experience as a problem setter, tester, or checker on competitive programming platforms is a plus.

What You'll Do

You will build maintainable C++ checker code, evaluate participant submissions, and help refine problem statements and test cases to ensure robust, fair evaluation.

• Design and implement checkers for problems with multiple valid outputs.
• Evaluate submissions against complex problem statements, including Codeforces-style tasks.
• Handle edge cases and diverse outputs efficiently using well-documented C++ code.
• Collaborate with the project team to clarify ambiguous scenarios and refine requirements.
• Document checker logic and provide feedback on test case coverage and solution quality.

Requirements

Candidates must be detail-oriented, analytically strong, and comfortable working independently in a remote, collaborative environment.

• Competitive programming and coding problem analysis experience.
• Advanced proficiency in C++.
• Strong analytical ability with complex constraints and multiple solution paths.
• Clear written and verbal communication.
• Meticulous attention to detail for code validation and output consistency.
• Experience working independently in a remote, collaborative environment.

Helpful Background

Prior experience as a problem setter, tester, or checker on major competitive programming platforms is a plus and will strengthen your application.

• Codeforces profile or other competitive programming handles and proof of participation or medals are requested in the review criteria.

Schedule, Pay, and Engagement

This is a contractor, part-time role with remote work allowed worldwide (English required). The posting indicates at least 15 hours per week in the description and a time-requirement field of 20+ hours/week; expect part-time engagement generally in that range.

Payment is pay-per-hour. The client posts an hourly range of $40–$80 per hour (hourlyRate up to $80).

• Employment type: Contractor, Part-time.
• Minimum listed availability: at least 15 hours/week; time-requirement field: 20+ hours/week.
• Pay model: hourly ($40–$80/hr; hourlyRate up to $80).
• Work is fully remote and worldwide (English required).

Review Criteria & How To Apply

When applying, highlight your competitive programming history, relevant C++ work, and availability to start quickly. Provide links to your Codeforces handle or similar profiles and any proof of participation or medals.

Be prepared to demonstrate sample checker code or past checker/tester work if requested during review.

• Required in application: Codeforces handle and profile link where applicable.
• Review factors: ability to start quickly and competitive C++ participation history.
• Include examples or links showing relevant problem-setting, testing, or checker work when available.