Call for Tasks

The EJOI 2026 Scientific Committee is pleased to invite the competitive programming community to participate in the design of the EJOI 2026 competition tasks.

Competition Tasks

EJOI tasks, similarly to IOI tasks, generally focus on the design of efficient and correct algorithms. Input and output should be kept as simple as possible. The EJOI needs both simple and difficult tasks that are creative and suitable for junior students. Generally, we encourage smaller length of expected solutions for the tasks.

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 EJOI competition tasks can provide, for example, a good guide on the desired composition of tasks. They can be found here and here.

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 “interactive” and “output-only” tasks that have occasionally been used in past EJOIs. Tasks with some measure of solution effectiveness other than CPU time consumption are encouraged.

A syllabus listing material generally considered acceptable for EJOI tasks can be found here. This syllabus is similar to the IOI syllabus but some topics are restricted or excluded – mostly data structures. 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 EJOI 2026 contestants;
• the tasks must not have been used in any recent similar competition;
• the tasks must be solvable by EJOI competitors during an EJOI contest round;
• the task descriptions must be unambiguous and easy to understand;
• the tasks must be original and/or innovative.

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 EJOI or national olympiad.

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 EJOI 2026. After that, authors are free to do whatever they wish with the tasks.

Submission process

Task materials should be placed together in a single file (use .zip for multiple files) and submitted to the scientific committee email address ejoi26tasks@uoi.ua.

Notes

Note that by submitting the task, the author asserts that he or she is authorized to grant, and does grant EJOI, an exclusive license to use the material until the EJOI 2026 has finished and a perpetual non-exclusive transferable license to reproduce the material. The author guarantees that the requirements of this call for tasks are met and that the materials will not be disclosed to any third party during the duration of the exclusive license.

Authors of all submitted tasks will receive feedback. Authors of tasks included in the actual competition will also be acknowledged by having their name, affiliation, and country included on the official EJOI 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.

What happens next

Receipt of submissions will be acknowledged via the contact address provided. The Host Scientific Committee will carefully review all submissions and select the tasks suitable for EJOI. Then these tasks are shared with the ISC. Finally, a shortlist of around 9 tasks is selected, six of which will eventually be given in the EJOI 2026 competition.

The authors of shortlisted tasks will be invited to attend EJOI 2026 in Lithuania as guests (authors will be responsible for their travel, but EJOI 2026 will cover their stay).

Summary

• Submission deadline: 3rd May 2026, Sunday
• Language: English
• Text format: PDF preferred
• Multiple files for one task (e.g., diagrams, solution code): in a single zipped 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 e-mail: ejoi26tasks@uoi.ua

Direct questions about the call for tasks to scientific committee email address ejoi26tasks@uoi.ua.