Why 42?

The 42-minute time limit is inspired by The Hitchhiker’s Guide to the Galaxy by Douglas Adams.

“The Answer to the Ultimate Question of Life, the Universe, and Everything is 42.”

— Deep Thought, after 7 million years of calculation

That’s why participants get exactly 42 minutes to solve the problems.

Why “Proggy” and “Buggy”?

The main characters of the contest problems are Proggy and Buggy. Proggy comes from the word “program,” while Buggy refers to programming bugs and errors.

Proggy is a highly skilled and creative programmer, while Buggy occasionally causes unexpected errors and complications that Proggy must overcome.

Why Participate in the Proggy-Buggy Contest?

Proggy-Buggy Contest is not just about solving problems — it’s about gaining experience, testing yourself, and enjoying the challenge.

By participating, you can:

• Try competitive programming without spending hours on a contest
• Discover your strengths and gaps in algorithms and logic
• Compare your approaches with other participants after the contest
• Meet other participants, especially if you join an offline hub

Unlike many programming contests, Proggy-Buggy Contest:

• lasts only 42 minutes
• includes unusual and fun problems
• is beginner-friendly while still challenging for experienced participants

👉 Even if you are just starting, Proggy-Buggy Contest is a great way to try competitive programming in a friendly, low-pressure format.

You do not need to solve all 13 problems to have a successful contest experience.

Place and Time

The contest is held twice a year:

• Towel Contest on May 25th — individual participation only
• Proggy-Buggy Contest at the end of October — team participation only

Why Towel?

The Spring contest is traditionally held on Towel Day, celebrated worldwide on May 25th by fans of Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy.

Online or Offline?

The contest is held online, but participants can also join from selected DataArt offices and partner hubs worldwide.

The list of available offline locations will be published on the registration page and sent to all registered participants before the contest.

When Does the Contest Start?

The contest starts and ends at the same time for all participants worldwide.

Before the contest, organizers send participants a link to the official YouTube livestream. The time announced in advance refers to the start of the livestream, not to the beginning of the 42-minute contest itself.

During the livestream, organizers:

• repeat the contest rules,
• answer participants’ questions,
• and officially announce the start of the contest timer.

That’s why it is important to join the livestream on time so you do not miss the beginning of the contest.

Registration

Registration opens approximately one month before the contest and is required for every participant.

Registration takes place through the official contest page after the contest is announced.

How to Register for the Towel Contest

To register for the Towel Contest, you need to:

• Create an account or make sure you still have access to your existing account
• Fill in the registration form
• Follow the instructions in the confirmation email

⚠ Registration closes one day before the contest. It is not possible to register on the contest day.

How to Create an Account

1. Go to the Training page and open any available contest.
2. Click Create Account in the top menu.
3. Fill in all required fields and choose the participant category that best matches your experience level.
4. Check your email and follow the confirmation link.
5. Confirm your account within 24 hours. Unconfirmed accounts are automatically removed.

After creating an account, you can start practicing using previous contests. The same account can be used both for practice contests and official participation.

Forgot Your Login or Password?

• Forgot your password? Use the password recovery option on any Training contest page.
• Forgot your login? If you cannot recover it, you may need to create a new account.

Participants

The contest has three participant categories based on programming competition experience.

All categories receive the same problems. Categories affect ranking only.

Amateurs

Participants with little or no experience in international programming competitions. This category is suitable for beginners and participants with university, city, regional, or national-level contest experience who have not participated in international Olympiads such as ICPC or IOI.

Professionals

Participants with experience in international programming competitions, including ACM ICPC / ICPC-style contests, IOI, and other international Olympiads, but who were not finalists or winners of major international competitions.

Superheroes

Top-level competitive programmers, including participants, who ranked in the Top 10 of major ICPC or IOI competitions, finalists and winners of major international Olympiads, and previous Proggy-Buggy Contest winners in any category.

⚠ During team contests, the team category is determined by the highest category among all team members.

👉 If you are unsure which category to choose, contact the organization team before registration.

Problems and Solutions

Contest Format

All problems in the contest are labeled with letters: A, B, C, D, and so on.

You can solve problems one by one or skip a problem and return to it later. Managing your time is an important part of the contest strategy.

What Kind of Problems Should You Expect?

Most contest problems involve:

• algorithms,
• logic puzzles,
• math and string manipulation,
• tricky or unusual problem statements.

Some problems may intentionally have no solution at all — this is part of the Proggy-Buggy concept and challenge.

You can practice solving problems in the Training Section.

Programming Languages

Participants can use many programming languages, including:

• C / C++
• Java
• C# (Mono)
• Python
• Ruby
• PHP
• JavaScript
• Free Pascal

The full list is available in the Programming Languages and Compilers section.

How to Submit a Solution

• Open the problem (A, B, C, and so on).
• Read the statement carefully.
• Write your solution and save the file.
• Open the Submit a Solution section on the problem page.
• Choose the programming language.
• Upload your code file.
• Click Send.

Multiple submissions are allowed.

Video Guide - https://www.youtube.com/watch?v=vnFwxdx5Egg

What Does “UNDECIDABLE” Mean?

Some problems in Proggy-Buggy Contest are intentionally undecidable. In such cases, participants must determine that the problem has no valid solution.

If you believe a problem is undecidable, your program must output exactly:

UNDECIDABLE

Example (JavaScript):

console.log("UNDECIDABLE");

👉 The key point is: don’t panic.

If a problem seems impossible:

• take time to analyze it carefully,
• compare it with other problems,
• decide whether to continue solving or mark it as UNDECIDABLE.

Understanding that some problems may truly have no solution is an important part of the Proggy-Buggy experience.

Video Guide - https://www.youtube.com/watch?v=qtmU5A07z2U

What Verdicts Can I Receive?

OK — correct solution
CE — compilation error
RT — runtime error
TL — time limit exceeded
ML — memory limit exceeded
WA — wrong answer
PE — presentation error
CF — check failed
SE — security restriction violation

Rules

General Rules

• Participants must rely only on their own knowledge and problem-solving skills during the contest.
• The use of AI tools, including ChatGPT and similar services, is prohibited during the contest.
• Participants may use only materials and information officially provided by the organizers before the start of the contest.
• Communication with coaches, mentors, or external participants during the contest is prohibited.

Contest Environment

• The contest starts and ends simultaneously for all participants worldwide.
• Multiple submissions are allowed.

Communication

Official contest communication is conducted in English.

Disqualification

Participants or teams may be disqualified and removed from the standings for:

• using prohibited tools or external assistance during the contest,
• using AI tools, including ChatGPT and similar services,
• cheating or attempting to gain an unfair advantage,
• violating contest rules,
• attempting to interfere with contest systems or infrastructure.

Organizer representatives at offline hubs may monitor participant behavior during the contest. In addition, submitted solutions — especially those of top-ranking participants and teams — may be reviewed after the contest for signs of cheating or AI-generated code. If violations are detected during this review, participants or teams may be disqualified and removed from the final standings.

Participation Restrictions

Participants residing in the territory of the Russian Federation, as well as in other sanctioned territories, are not allowed to take part in the Proggy-Buggy Contest.

Additional Rules for Team Contest

• All team members must belong to the same participant category. The team category is determined by the highest category among all team members.
• Team members may participate from different cities or countries, except sanctioned territories.
• Teams may use voice or text communication tools (Zoom, Telegram, Discord, etc.) only for communication within their own team.
• Each team must use only one contest account.
• Solutions must be submitted from a single device only.
• If organizers detect submissions from multiple devices, the team may be disqualified.
• Team members are not allowed to receive help from coaches, mentors, spectators, or other external participants during the contest.

Penalties and Scoring

How Are Winners Determined?

The contest uses ICPC/ACPC-style scoring rules.

The winner is the participant or team that solves the highest number of problems with the lowest penalty time.

How Does Penalty Work?

The contest includes two different types of penalties:

• penalty time for incorrect submissions before an accepted solution;
• score deduction (-1) for incorrectly marking a solvable problem as UNDECIDABLE.

Both mechanics are important parts of the contest strategy.

Penalty time is calculated only for solved problems.

For each solved problem:

• the time from the beginning of the contest to the first accepted solution is counted;
• 20 penalty minutes are added for each rejected submission made before the accepted one. Unsolved problems do not add penalty time.

Example

If a participant solves a problem:

• 15 minutes after the start of the contest,
• after 2 incorrect submissions,

the penalty for this problem will be:
15 + 40 = 55 penalty minutes.

👉 This means that solving problems quickly and avoiding incorrect submissions are both important parts of the contest strategy.

How Are UNDECIDABLE Problems Evaluated?

Some Proggy-Buggy problems may intentionally have no solution.

If a participant correctly identifies such a problem and submits UNDECIDABLE, the problem is counted as solved.

However, if a participant submits UNDECIDABLE for a problem that actually has a valid solution, the participant receives -1 for that problem.

This rule exists to prevent random guessing and encourage thoughtful analysis of each task.

Example

• Correctly identifying an undecidable problem: +1
• Marking a solvable problem as UNDECIDABLE: -1

If the participant later correctly solves that problem, the score is adjusted back to 0.

Standings and Results

Contest standings are hidden during the contest and become available only after the publication of the preliminary results.

Preliminary results are usually published within 2–3 days after the contest.

After the preliminary results are announced, participants have 3 days to submit an appeal or report a possible issue related to judging results.

The organizing team may take up to one additional week to review appeals and complete the final verification process.

Official contest results are usually published within two weeks after the event.

After the official results are announced:

• winners and participants receive certificates and diplomas,
• prize distribution begins.

Participants or teams may be removed from the final standings if violations are detected during post-contest review.

Winners and Awards

Winners are determined within each participant category — Amateurs, Professionals, and Superheroes — regardless of whether the contest is held in individual or team format.

Main Awards

The contest recognizes:

Honorary 1st Place Honorary 2nd Place Honorary 3rd Place

for participants and teams in each category.

Additional Awards

Additional prizes may be awarded for:

• the first correct solution to a problem,
• the shortest correct solution to a solvable problem,
• the first correct identification of an undecidable problem,
• outstanding performance with the lowest penalty time.

Prizes

Winners receive gift cards and DataArt presents.

Prize delivery is arranged individually after the publication of the official results.

Certificates

All participants receive participation certificates after the publication of the official contest results.