European Junior Olympiad in Ynformatics 2027

About eJOY

The European Junior Olympiad in Ynformatics (eJOY) is an informatics contest held online annually with a main goal of having fun rather than prestige. For information regarding the type of problems at the competition, you can check out the previous editions. If you're interested in participating, you can join our Discord server and contact the organizers.

Standing

Day 1 - standing

• Task statements: apples, redica, bribe2, minecraft
• Task editorials: apples, redica, bribe2, minecraft
• Tests and author solutions: apples, redica, bribe2, minecraft
• Results from the grading system
• Submissions of the participants

Day 2 - standing

• Task statements: ezici, nod2, knapsack
• Task editorials: ezici, nod2, knapsack
• Tests and author solutions: ezici, nod2, knapsack
• Results from the grading system
• Submissions of the participants

Practice session - standing

• Task statements: A-B, guess, tree, tree2
• Task editorials: A-B, guess, tree, tree2
• Tests and author solutions: A-B, guess, tree, tree2
• Results from the grading system
• Submissions of the participants

Contest rules

• The eJOY Organizing Committee reserves its full rights to do whatever crazy things they come up with, with any aspect of the problems and the contest itself.
• Using the internet or any external help, including files on the device, are strictly prohibited during the contest, unless the problem requires it.
• The contest is held online and lasts two days. Each day contestants get three or four tasks, such that the total number of problems is 6 or 7.
• Before the first day of the contest, a practice session is held. These rules apply to the practice session too. Contestants can use it to familiarize themselves with the BOS grading system (docs).

Submission rules

• Solutions are written in C++, unless the task requires otherwise.
• C++ solutions must compile on the worker machines in at most 30 seconds and must use at most 1024 MB compilation memory.
• At most 50 submissions and 50 user tests (if allowed) can be uploaded for each problem.
• Contestants can submit on the same problem at least 30 seconds after the time of the last submission on the respective problem (submitting on other problems in the meantime is allowed); this restriction is removed in the last 15 minutes of the competition for every competitor. The same also applies to user tests.

Schedule

Organizing Committee

Grading system

All solutions are judged automatically by the grading system via multiple worker machines. The Arena has a live archive of previous problems where contestants can submit on them.