Call For Tasks


The IOI Scientific Committee invites everyone in the IOI community to submit tasks for the IOI 2010 competition. The deadline for submitting tasks is March 20, 2010; rough guidelines for tasks and instructions for submission are given below.

IOI Competition Tasks

IOI tasks are typically focused on the design of efficient, correct algorithms. Input and output are to be kept as simple as possible. The competition tasks from previous IOIs can provide, by example, good guidance on the desired composition of tasks; a large collection can be found at the IOI site at

However, the nature of previous tasks should not constrain the design of new tasks; the submission of novel task types not yet seen in IOIs is encouraged. We are particularly interested in tasks whose basic rules (if not optimal strategy) are accessible to a wide audience, and tasks that illustrate algorithms and computational problems that arise in a variety of human endeavours. Open-ended tasks -- ones 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 batch processing format, in which a program reads a text file, performs some computation, and outputs a text file. Examples include "interactive" and "output only" tasks which have been used occasionally in previous IOIs, as well as reactive, animated, or multiplayer tasks. Tasks with some measure of solution effectiveness other than CPU time consumption are encouraged.

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

To ensure a fair and interesting competition for all, tasks should satisfy the following conditions:

  • The tasks should not have been seen by any potential IOI 2010 contestants.
  • The tasks should not have been used in any similar competition.
  • The tasks should be solvable by IOI competitors during an IOI contest round.
  • The task descriptions should be unambiguous and easy to understand.
  • The tasks should be culturally neutral.
  • The tasks should be original and/or innovative.

What to Submit

A task submission must contain a statement of the task in English, preferably formatted in plain text. If diagrams are needed as part of the task description, they should be attached separately. In addition, the submission must also contain a description of the desired solution to the task (a description of an algorithm which should receive full marks). While not strictly required, it is strongly preferred that the submission also includes at least one implementation of the desired solution (in C/C++ and/or Pascal). Analyses of alternative solutions, suggestions for grading, test data or ideas for generating test data, the motivation behind the task, and any comments related to the task are also welcome and would be highly appreciated.

A task submission must also include a contact address (preferably one e-mail 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 2009 to IOI 2010.

Submitted tasks must be kept in strict confidence until the end of IOI 2010. At this time, authors are free to do whatever they wish with the tasks, but may be asked to have them considered for IOI 2011, in which case strict confidence would have to be maintained through IOI 2011.

All authors will be acknowledged at the close of IOI 2010.

How to Submit

Task materials must be placed together in a single file (use .zip or .tgz for multiple files) and submitted via the Web at

To access this site, please enter the credentials

username: IOI2010
password: Canada

Please do not encrypt your submission: the upload page will do this automatically.


Please note that by submitting the author asserts that he or she is authorized to grant, and does grant IOI an exclusive licence to use the material until August 31, 2010, and a non-exclusive licence to reproduce the material in perpetuity. The author warrants that the requirements in this call for submissions are met, and that the materials will not be disclosed to any third party for the duration of the exclusive licence.

Task authors 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 IOI 2010 has ended. In case of doubt, contact the ISC. Note that we do not wish to forbid authors of submitted tasks to be involved in other competitions and training, but we do ask them to take all necessary precautions to safeguard confidentiality.

What Happens Next

Receipt of submissions will be confirmed via the provided contact address.

The IOI Scientific Committee will carefully review all submissions and will select a short-list of about 12 to 15 tasks, eight of which will eventually be given at the IOI 2010 competition.

The authors of the tasks selected for the short-list will be invited to attend the IOI 2010 as Invited Guests. However, they will not be informed prior to the competition as to whether their tasks will be used at the actual contest or whether their tasks have been substantially modified by the IOI Scientific Committee.

The authors of tasks included in the actual competition will also be recognized by listing their name, affiliation and country on the official IOI 2010 tasks booklet (unless they specifically decline this).


Submission deadline: March 20, 2010
Language: English
Text format: plain text preferred
Multiple files for one task (e.g. diagrams, solution code):
in single zip or compressed tar archive
Multiple tasks: submit separately
Minimum contents of submission:
Contact address (preferably e-mail)
Name, affiliation, country, and olympiad-role description of author(s)
Task description (including required diagrams)
Description of desired solution
Highly desirable:
Solutions coded in C/C++ and/or Pascal
Optionally include:
Suggestions for grading
Test data, test data specifications
Alternate solutions or expected near-solutions
Complexity analysis
Background information on the task
Any other comments relevant to the task