Call for Tasks - IOI 2025

The IOI 2025 Scientific Committee is pleased to invite the IOI community to participate in the design of the IOI 2025 competition tasks.

Competition Tasks

IOI tasks generally focus on the design of efficient and correct algorithms. Input and output should be kept as simple as possible. The IOI needs both simple and difficult tasks that are creative. We are actively encouraging submissions of easy problems. While challenging problems are essential, we believe that including interesting problems with lower difficulty can be equally engaging. These problems should still require creative problem-solving skills and have interesting solutions. We especially encourage submissions of easy problems that can be solved in multiple ways.

Previous IOI competition tasks can provide, for example, a good guide on the desired composition of tasks, the last 8 are listed below:

  • The tasks from IOI 2024 may be found Here
  • The tasks from IOI 2023 may be found Here
  • The tasks from IOI 2022 may be found Here
  • The tasks from IOI 2021 may be found Here
  • The tasks from IOI 2020 may be found Here
  • The tasks from IOI 2019 may be found Here
  • The tasks from IOI 2018 may be found Here
  • The tasks from IOI 2017 may be found Here

A large collection can be found on the IOI site here.

However, the nature of past tasks should not restrict the design of new tasks; submissions of new types of tasks not yet seen at IOIs are encouraged. We are particularly interested in tasks whose basic rules (if not an optimal strategy) are accessible to a wide audience, and tasks that illustrate algorithms and computational problems arising in a variety of human endeavors. Open-ended tasks, those that do not necessarily have a known efficient or optimal solution, are welcome.

We are also particularly interested in tasks that go beyond the typical format where a program collects input, performs some computation, and outputs results. Examples include "reactive" and "output-only" tasks that have occasionally been used in past IOIs. Tasks with some measure of solution effectiveness other than CPU time consumption are encouraged.

A syllabus listing material generally considered acceptable for IOI tasks can be found here. The syllabus is not meant to be restrictive, but rather to serve as a guideline for task preparation.

To ensure a fair and interesting competition for everyone, the tasks must satisfy the following conditions:

  • the tasks must not have been seen by any potential IOI 2025 contestants;
  • the tasks must not have been used in any recent similar competition;
  • the tasks must be solvable by IOI competitors during an IOI contest round;
  • the task descriptions must be unambiguous and easy to understand;
  • the tasks must be original and/or innovative.

For further reading, the ISC procedures and policies document contains a brief description of the task selection process applied by the ISC over the recent years.

Task criteria

A task submission must contain:

  • Statement in English, preferably formatted in PDF with required diagrams and pictures included.
  • Description of the desired solution (a description of an algorithm which should get full score).
  • Contact address (preferably an email address) and background information on the task author(s): affiliation, country, and a description of the author's role in the IOI or national olympiad, including training duties, over the period from IOI 2023 to IOI 2025.
  • If you want the ISC to provide feedback on your submission, you should also provide a PGP key ID along with the submission.
It is also strongly recommended that it contains:
  • At least one implementation of the desired solution in C++.
  • Analysis of alternative solutions.
  • Suggestions for grading.
  • Test data or ideas for generating test data.
  • The motivation behind the task.

Any comments related to the task are also welcome and would be highly appreciated.

Submitted tasks must be kept in strict confidence until the end of IOI 2025. After that, authors are free to do whatever they wish with the tasks, but may be asked to have them considered for IOI 2026, in which case strict confidence would have to be maintained through until IOI 2026.

Submission process

Task materials should be placed together in a single file (use .zip or .tgz for multiple files) and submitted online here. When submitting a task, you will need to enter the authorization code "pacha", Do not encrypt your submission: the upload page will do it automatically.

Notes

Note that by submitting the task, the author asserts that he or she is authorized to grant, and does grant IOI, an exclusive license to use the material until the IOI 2025 has finished and a perpetual non-exclusive transferable license to reproduce the material. The author guarantees that the requirements of this call for submissions are met and that the materials will not be disclosed to any third party during the duration of the exclusive license.

Authors of tasks and their collaborators must not use a submitted task, or a variant thereof, or techniques specific to that task, in any competition or training until the IOI 2025 has ended. If in doubt, contact the ISC. Note that we do not wish to prohibit authors of submitted tasks from participating in other competitions and training, but we ask that they take all necessary precautions to safeguard confidentiality.

What happens next

Receipt of submissions will be acknowledged via the contact address provided. The Scientific Committee will carefully review all submissions and select a shortlist of around 10 tasks, six of which will eventually be given in the IOI 2025 competition.

The authors of shortlisted tasks will be invited to attend IOI 2025 in Bolivia as guests (authors will be responsible for their travel, but IOI 2025 will cover their stay). However, they will not be told before the competition whether their tasks will be used in the actual contest or whether the Scientific Committee has substantially modified their tasks.

Authors of all submitted tasks will receive feedback from the ISC. Authors of tasks included in the actual competition will also be acknowledged by having their name, affiliation, and country included on the official IOI website (unless specifically declined by them). Problems from tasks included in the actual competition will be available under a Creative Commons Attribution (CC-BY) license.

Summary

  • Submission deadline: December 29th, 2024
  • Language: English
  • Text format: PDF preferred
  • Multiple files for one task (e.g., diagrams, solution code): in a single zipped or tarred archive
  • Multiple tasks: submit separately
  • Minimum submission contents:
    • author information: name, email, affiliation, country, and role in olympiad
    • task statement
    • description of the desired solution.
  • Also recommended:
    • solution implementations in C++
    • suggestions for grading
    • test data
    • alternative or near-expected solutions
    • general information about the task
    • any other comments relevant to the task.
  • Submission site: https://isc.ioinformatics.org/taskbox/, the authorization code is "pacha".
Direct questions about the call for tasks to scientific committee email address hsc@ioi2025.bo.