Schedule

NYPC 2026 consists of a Qualification Round (QR) and a Final Round (FR).

In the Rookie Track, a single heuristic problem is given in each round.

For the practice problem and the Qualification Round, a single problem is given of two sections.

• Step Up: Multiple inputs of step-by-step difficulty are given directly to the participant. The participant solves these and submits the output file of the specific input.
• Challenge: The participant submits code that takes the problem's input and produces the correct output.

A problem presented in the Final Round consists of only a Challenge section.

Qualification Round

• Registration: 2026-06-04 13:00 KST
• Practice problem opens: 2026-06-04 13:00 KST
• Qualification Round starts: 2026-07-10 10:00 KST
• Qualification Round ends: 2026-07-19 22:00 KST
• Replay submission deadline: 2026-07-20 23:59 KST

Before the Qualification Round begins, you can test the environment for the competition in advance through the practice problem. The score of the practice problem is not reflected in the total score and does not affect your final Qualification Round score.

A single problem is given per round, and participants must solve the problem and submit their code or answer before the round ends.

After the competition ends, each participant must submit a replay of their problem-solving process within the submission deadline.

Final Round

The top ~80 participants in the Qualification Round can participate in the Final Round held in Seoul on August 29.

The detailed schedule will be announced later.

• Entry is not permitted after the entry deadline.

Solving Problems and Evaluation

The score of the whole problem is weighted average of scores of each section.

Both the Step Up section and the Challenge section have a maximum score of $1\,000\,000$ points, and are reflected at a specific ratio. The ratio is specified in the problem.

For example, if the Step Up section accounts for $20$% and the Challenge section accounts for $80$%, then a participant who earned $x$ points in the Step Up section and $y$ points in the Challenge section has a score of $0.2x + 0.8y$. Therefore, the maximum score of the problem is also $1\,000\,000$ points.

Step Up

The participant can see the list of inputs (test cases) given on the problem page.

Each input can be directly or check through the simulator.

The participant submits as their output file only for an input generated using the simulator, code, or other tools.

• The inputs are fixed, and are not changed, added, or removed during the competition.
• The answer must be 1 MiB (1048576 bytes) or less.
• After the submission, automatic grading begins. You can check the result after grading is done.
• The answer can be submitted multiple times, and the final score for each input is the highest score among the submitted answers.
• The score of the Step Up section is calculated as the sum of the scores for all inputs.
• The score is calculated and displayed as an integer.

Challenge

The participant can review the problem statement of Challenge section. In addition, example codes are given to help solving the problem.

The participant can submit one source code that reads input and produces output, and one optional binary file that can be read and used via file I/O during the code execution.

• Code must be 1 MiB (1048576 bytes) or less, and the binary file must be 10 MiB (10485760 bytes) or less.
• The binary produced as a result of compiling the code (or, for languages using an interpreter, the code file) and the binary file uploaded directly are located in the same directory during execution.

The grading result of each test case is expressed as a "cost". An answer with a lower cost is a better answer.

Sample Test

As soon as the participant submits the code and binary, the participant can check the output and results for the sample input.

The Sample Test is intended as the server-side check for the code, and is not reflected in the System Test.

• The sample input used in the Sample Test is fixed and disclosed to the participant.
• The participant can check the output for each sample input and its cost.

Pretest

The participant can select one of the submissions that used cutoff cost or less in Sample Test as main submission.

The Pretest runs periodically using the main submissions each participant selected.

• If no main submission is selected, the latest submission among those that used cutoff cost or less in the Sample Test is selected as the main submission.
• The main submission can be changed freely during the round, and up to 1 hour after the round ends.

For the Pretest, random inputs are generated.

• The number of inputs for the Pretest is the same in all Pretests.
• The inputs for the Pretest may differ for each Pretest.
• The method of generating the inputs for the Pretest are specified in the problem.

All main submissions are evaluated using the inputs for the Pretest.

• The participant can check the following information. -Each input carn be downloaded or checked through the simulator.
  • For each input, the participant can check the output and the result. Based on this result, a ranking is assigned for each input.
  • For each input, the participant can check ranking and the score calculated based on it. Therefore, the participant can check their own Pretest score.
  • The detailed score calculation formula is at below.
• The participant cannot check the following information.
  • For each input, the participant cannot check other participants' per-input results or rankings.
  • The participant cannot check which rank Pretest score occupied among all participants. Therefore, the participant cannot check their own Pretest ranking.

The goal of the Pretest is to let participants roughly estimate their own performance. Therefore, the results of the Pretest are not reflected in the System Test.

System Test

For the System tests, random inputs are generated.

• The number of inputs for the System Test may be greater than the number of inputs for the Pretest.
• The method for generating the inputs for the System Test are specified in the problem.

The organizer evaluates all main submissions using the inputs for the System Test, and this becomes the final result the participant earns in the Challenge section.

• The detailed score calculation formula can is at below.

Score Calculation and Performance

The score of a displayed evaluation is equal to the average of the relative scores that the participant's main submission received on the inputs used in that evaluation. For the detailed calculation formula of the relative score, please refer to the section below.

Participants who find it difficult to roughly determine their position among participants by relative score can gauge it through their expected performance. The performance expresses the relative score in an easy-to-read way by applying rules similar to ELO. The performance itself has no effect on the evaluation.

Pretest and System Test Relative Score

The score of each input is determined by how superior the participant's output is compared to other participants.

The specific calculation method is as follows.

$$\textrm{Score} = \left\lfloor 10^6 \cdot \left(1 - 0.5 \sqrt{\frac{n_\textrm{lose} + 0.5n_\textrm{draw}}{n_\textrm{tot}}}\right) \right\rfloor$$

Here, $n_\textrm{lose}$ is the number of main submissions that received a better result than the participant's main submission, and $n_\textrm{draw}$ is the number of other participants' main submissions that received the same result as the participant's main submission. $n_\textrm{tot}$ is the total number of participants who took part in the evaluation.

Pretest Performance

The performance is calculated using the average score of the test cases used in the Pretest. Higher performance corresponds to better score and grade.

The performace $P$ is calculated as follows:

$$\begin{aligned} \textrm{rank}_\textrm{avg} &= (2(1-\textrm{Score}_\textrm{rel}))^2 \times n_\textrm{tot} + 1 \\ z &= \sqrt{2} \times \textrm{erf}^{-1}\left(1 - \frac{(\textrm{rank}_\textrm{avg} - 0.5)}{n_\textrm{tot}}\right) \\ p' &= 1500 + 400 \times (\sqrt{2} \times z) \\ P &= \begin{cases} 0 & \text{if } p' \textrm{errors on calculation} \\ 300 \times \exp((p'-300)/400) & \text{if } p' < 300 \\ p' & \text{if } 300 \le p' \le 2700 \\ 2700 + 400\log ( 1 + (p'-2700)/400) & \text{if } p' > 2700 \end{cases} \end{aligned} \\$$

Rules per Round

Practice Problem

• You can submit code twice every 5 minutes.
  • If you submit code two or more times within 5 minutes, additional submissions become available 5 minutes after the time of the first (second-to-last) submission, not the second (last) submission.
  • The submission interval and count may change at the organizer's discretion.
• Before the Qualification Round begins, every day at 6 PM (KST), the Pretest is run based on the code each participant selected as their main submission.
• A System Test is not run for practice problem, and is not reflected in the final results.

Qualification Round

• You can submit code twice every 5 minutes.
  • If you submit code two or more times within 5 minutes, additional submissions become available 5 minutes after the time of the first (second-to-last) submission, not the second (last) submission.
  • The submission interval and count may change at the organizer's discretion.
• Every day at 10 AM, 3 PM, and 9 PM, the Pretest is conducted based on the code each participant selected as their main submission.
  • The Pretest is only for a reference and does not affect the System Test.
• After the System Test, the score for the Challenge section is finalized.
• The weighted average of the scores the participant earned in the Step Up section and the Challenge section becomes the final score.

Final Round

• You can submit code once every 10 seconds.
• Starting 1 hour after the competition begins, the evaluation is conducted at least 10 times at designated points based on the code each participant selected as their main submission.
• On the day of the competition, you can check information about each Pretest at the venue.
• The score the participant earned in the System Test becomes the final score.

Tiebreaker

• If a tie occurs, the participant whose main submission has the earlier submission time has the higher ranking.

Execution and Grading Environment

The execution and grading of all submitted code is performed in the following environment.

• Amazon Web Services c7a.2xlarge instance
• Custom processor based on 4th-generation AMD EPYC
• Clock: 3.7 GHz
• Processor architecture: 64-bit
• OS: Ubuntu 24.04

Please note that code that does not work in this environment will not be graded. For more informations on the compilers used for each language and the specific development environment, please refer to the "Dev Tools Guide" page. Elapsed time and consumed memory are determined based on the resources used by the process in which the source code submitted by the participant is executed.

• The time limit measures the time process occupied the CPU (CPU time).
• The memory limit measures the amount of memory the process uses. This includes not only the variables and arrays declared by the user, but also the libraries (header files, modules, etc.) used per language and the memory allocated to the process by the operating system.
• Solving the problem using multiple threads is also possible. However, only one CPU core is allocated to the program, and when measuring the time and memory limits, the time and memory of all threads are summed.

Grading Results

Step Up Section

If you click a submission under "Submissions" at the top right of the problem-solving screen, you can look up which input the output was submitted for and its result. The details of each result are as follows.

• OK - The case where all conditions were satisfied and it was processed as correct.
• Partial Score - The case where the submitted output is valid and received a partial score as a result of grading.
• Wrong Answer - The case where the submitted output was processed as incorrect.
• IE (Internal Error) - The case where an unknown internal error occurred. If you receive this result, you must contact the organizer.

Challenge Section

• CE (Compile Error) - The compilation of the submitted source code failed.
• TLE (Time Limit Exceeded) - The case where the execution time of the submitted source code exceeded the time limit specified in the problem.
• WTLE (Wall Clock Time Limit Exceeded) - The case where the actual wall clock time of the submitted source code exceeded the set time limit. This is the case where the total execution time, not the time the process occupied the CPU, was exceeded, which may indicate that an error occurred during execution.
• RE (Runtime Error) - The case where an error occurred during execution. This error can also occur when the memory limit is exceeded, or the return code is non-zero.
• WA (Wrong Answer) - The case where the program terminated successfully, but the output was incorrect.
• IE (Internal Error) - The case where an unknown internal error occurred. If you receive this result, you must contact the organizer.
• OK - The case where the program terminated normally and the output earned a score.

Replay

After the round ends and before the replay submission deadline, each participant must submit a replay.

A replay is the particpant's problem-solving process in the time order. The length is between 1 and 10 pages, and it can be in any format, but it must be submitted as a PDF file.

A replay must include the followings:

• The overall timeline solving the problem (the Pretests or the submissions can be used as a reference)
• What difficulties were found in the submissions, what considerations were made, and how they were solved and/or why they could not be solved
• (If an LLM was used) which model was used and how it was used

The following content is not required, but it is recommended to include in addition.

• The approach to the problem, and the observations and considerations made to solve the problem
• Materials such as captures, photos, or code snippets that can visually show the problems you experienced or the process of solving them
• (If an LLM was used) what the limitations of the LLM were, if any, and how you overcome them, if you did
• Other points that were good, regrettable, difficult, interesting, or anything else you want to write
• Complaints about the competition system, problems, or points you thought would be good to improve

The replay is not included in the System Test evaluation criteria.

Additional Restrictions

A replay is a piece of writing what you experienced and felt. Even if you used an LLM to solve the problem, the problem-solving process and considerations contained in the replay must be written without an LLM, by yourself.

• Even when grammar correction or similars are needed, you must not use an LLM, but use a spell checker or similars.
• If all or part of the body appears to have been generated using an LLM, or if it cannot be confirmed that you solved the problem yourself, the organizer may request additional proof or modification of the replay.
  • However, inserting your own prompts or conversation history with an LLM into the replay for the purpose of supplementing is permitted exceptionally.
• Please take special care that your sensitive personal information is not included in the replay.

If a replay contains inappropriate expressions such as profanity or abusive language, your participation in the competition may be restricted or your award may be revoked at the organizer's discretion.

Problem-Related Questions

If there is an error in a problem or other issue that disrupts the competition including internal error, you can make a question by clicking the "Ask a Question" button on the problem page or by pressing the Ctrl + K shortcut in the coding area.

• If your question contains inappropriate expressions such as profanity or abusive language, you may be disqualified.
• Questions related to the solution of the problem will not be answered.

Examples of Invalid Questions

The followings are examples of invalid questions.

"It works on my machine, but the result is not shown correctly when graded."

• The provided testing tool may differ from the actual grading environment. Please double-check the problem's input/output format and so on.

"It works on my machine, but I get a compile error when I submit."

• The development environment used by the participant and the grading environment where the program is actually compiled and executed may differ. Please be sure to check the "Dev Tools Guide" page.

Answers

• Only problem-related questions are allowed. - This applies when the nature of the question is off-topic.
• Read the problem statement. - This applies when the question is judged to be sufficiently answered by the content written in the problem.
• No comment. - This applies when the organizer judges that the answer could in any way affect the participant's problem solving or the progress of the round.

Code of Conduct

You may receive penalties if cheating is detected. This includes and not limited to:

• For problems other than the practice problem, disclosing or leaking the problem and the problem-related algorithms, solutions, or source code to an unspecified people
• Discussing materials related to a problem other than the practice problem with others
• Submitting the code you do not have permission to use
  • Example 1: Code obtained through methods such as hacking
  • Example 2: Code obtained using methods such as reverse engineering (reverse analysis) of commercial programs
  • Example 3: Code obtained through other illegal methods
  • Even if the code is publicly available to an unspecified number of people on the internet, etc., it is considered to be without permission to use if the source is not indicated in comments or the like.
• Submitting code written by others after the start of the competition
• Taking the competition on behalf of someone, or solving problems with help from others
• Sharing or disclosing your personal ID and password to others
• The same person participating multiple times with multiple IDs
• Obstructing other people's participation in the competition or attacking the system
• Other acts that can commonly be regarded as cheating

Other acts may also be regarded as cheating at the organizer's discretion. If cheating occurs or is suspected, participation and award eligibility may be revoked at any time during the competition period. If the operation of the competition is disrupted, the organizer may pursue legal action.

The following acts are not cheating.

• Discussing or sharing the problem, problem content, solution methods, source code, etc. for the practice problem
• Using a code repository that others cannot see
  • However, if you use a chat room or code repository, please take special care with the visibility settings.
• Generating or modifying code using LLMs (ChatGPT, Copilot, etc.) and other coding assistance tools

If you are uncertain about whether an act is cheating, do not judge it arbitrarily; be sure to contact the organizer.

Program Usage Guide

• NYPC encourages the use of generative AI represented by large language models (hereafter LLMs) as a tool to help with creativity and problem solving.
• The core of the competition is to evaluate human creativity and problem-solving ability, and (whether one can access a large amount of computing resources) should not have a major impact on the competition.
• Therefore, the following uses of LLMs are explicitly prohibited.
  1. Obtaining a large amount of output from an LLM using an automated method
  2. Using multiple LLMs to output different code for the same purpose
  3. Selecting from a large amount of code or ideas using an LLM
• Using an LLM is not essential for participating in the competition, and you can participate without an LLM.

Permitted Examples

• Using an LLM to translate the problem and brainstorm ideas
• Using an LLM and an LLM-powered IDE (Codex, Claude Code, Gemini Code Assist, Cursor, etc.) to write and debug code
  • Using the IDE's Auto-complete, Ask, Plan Mode, etc.
• Generating answers using a Chain-of-thought approach
• Using a program in any way that does not use an LLM during execution
  • This does not mean that you must not run an automated program written with an LLM.
• Writing and evaluating code in large quantities by methods other than an LLM

Non-Permitted Examples

• Calling an LLM in large quantities using a script, then selecting and submitting code for the problem by a certain method
  • Even if you selected the code using a method that does not use an LLM, if the code was created with an LLM, it constitutes cheating.
• Using a single prompt, but the LLM autonomously generates a large amount of code and provides some of it to the user
• Including text written or modified by an LLM in the body of the replay by any method
  • Exception: Attaching or quoting a conversation with an LLM, or wording from it, verbatim in the replay is permitted.

Even if you do not directly prompt the LLM, if the LLM commits an act that constitutes cheating, you are the one who has committed cheating. All responsibility for the use of LLMs lies with you.

The organizer may request an explanation of the problem-solving process from participants if necessary, and participants must respond faithfully to this. You may also suffer penalties if a problem arises due to poor code management. When using LLM tools, you must opt out of having your data used for training.

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Q & A

Q1. LLM models use a Chain-of-Thought approach. Is this also large-scale generation of output using an API?

A1. No, even if Chain-of-Thought is used, it is not judged as large-scale generation if the query was done manually.

Q2. I asked an LLM the same question multiple times. Is this also treated as large-scale generation?

A2. No, it is not judged as large-scale generation unless the query was made by an automated method using an API or script. However, even if done manually, making dozens or more identical queries by simultaneously using multiple accounts or sessions may be treated as equivalent to large-scale generation.

Q3. Do the above restrictions also apply to code used for testing, even if it is not directly submitted code?

A3. Yes, they apply. Even if the code is not submitted, all code used when solving the problem must be written in compliance with the restrictions.

Q4. An LLM-equipped IDE automatically uses tool calls. Is this cheating?

A4. Basically, an IDE automatically using tool calls is not cheating, but it becomes cheating when that tool call involves an automated LLM tool call or evaluation of code generated by an LLM. The responsibility for supervising this tool use lies with you.

Q6. Is learning how to use an LLM from others cheating?

A6. Receiving help of any kind from another person for the purpose of competition use is cheating.

Q7. If externally generated code was created through large-scale code generation, can that code be used?

A7. Please refer to the "The following acts are not cheating." item above.

Q8. Can I use multiple LLM sessions in order to use multiple types of LLMs?

A8. You may use multiple LLM sessions as long as you do not use multiple sessions simultaneously.

Q9. Does the organizer provide an LLM for use?

A9. The organizer does not provide an LLM.

Q10. Can AI models and generative AI be used inside the code submitted in the competition?

A10. It is possible as long as it fits within the source code and binary size limits. However, the competition environment does not have network communication. For details, please refer to the "Dev Tools Guide".