Call for Problems

We are pleased to announce the Call for Problems (CfP) for the 2023 edition of the Winter Contest.

Submitters of selected candidate problems will become part of the Winter Contest 2023 Jury. They are expected to assist in the preparations of the final contest problem set. Questions regarding this call can be posed to:

Selection Procedure

The deadline for submitting candidate problems is December 3, 2022.

Selection criteria include problem novelty, and the goal of making a well-balanced problem set in terms of algorithmic topics, and degrees of problem difficulty. You are encouraged to submit at least two candidate problems for consideration rather than one.

If your problem(s) are accepted, you will become part of the Winter Contest 2023 Jury. You are expected to have time available in the period from December to late January, in order to discuss improvements to your (and other jury members') problems. You are also expected to become a proofreader and implementer of at least one selected problem that is not your own.

If your problem(s) are not accepted, we will destroy all records kept of them. This allows re-submission of the problem(s) for use in another contest.

More information on the submission requirements, the submission process and simultaneous submissions can be found below.

Submission Guidelines

Problem submissions should adhere to the following guidelines:

  • Submissions should be original, i.e., they should never have been used before in any other contest.
  • Submissions should include a Problem Statement in clear English.
  • The Problem Statement should include a clear discussion of expected input and output formats, as well as allowed parameter values.
  • The Problem Statement should include sample input and output files, one input per file.
    Note: it is possible that your problem does not conform to the standard “fixed input -> fixed output” format; for example, if multiple outputs are possible for a given input, or if the input is generated dynamically using an interactive program. This is fine as long as the problem text is clear on the subject. In case your problem requires a non-standard checker program, you are encouraged to provide it with your submission.
  • The submission should include two separate, short files:
    • explaining the idea of the problem;
    • explaining the idea of the solution and the algorithm to be used.
    Please keep the spoiler-free.
  • The should give an assessment of the difficulty of the problem. This is a number between 0 and 100, indicating the percentage of Winter Contest teams that is expected NOT to solve the problem (so higher means more difficult).

We will need a variety of problem difficulties to make a well-balanced problem set. Do not hesitate to submit (relatively) simple problems for consideration.

Submission Format

Please use the following setup for problem submission.

  • It is preferred (but not mandatory) if your Problem Statement is delivered in LaTeX format. Before the contest, the problems will be stylistically homogenised and typeset using LaTeX.
  • Please put all relevant files of your submission in a single directory containing one subdirectory per problem, and ZIP this directory.

We will be using the official ICPC problem format. If you want to use it when submitting your proposal the format is documented here:

You can find example problem packages here.

Submission Procedure

Send the submission to:


Competitive Programming Ulm
AltaSigma GmbH
Thank you to AltaSigma GmbH, who kindly sponsored the infrastructure the contest judge runs on.

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