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IOI 2023 was hosted by Hungary. Visit the official website to learn more.

Just finished   IOI 2023 in Hungary

IIOT Contests 2021/22

For the fifth time, the International Informatics Olympiad in Teams is taking place and will be mirrored into online rounds. These contests have a lower difficulty level than those of the IOI, and are intended for teams (up to 4 contestants) of students from the same high school. Everyone is welcome to participate, especially if you are considering joining officially the IIOT in the future!

More specifically, we allow:

  • several teams from the same school (also in the official contest)
  • teams participating only in some contests (also in the official contest)
  • smaller teams (also in the official contest) and larger teams
  • teams of students from different schools and non-students
  • changes in team members between contests

The mirror contests timing will be USACO-like: it will be open for 24 hours but you will be able to compete for up to 3 hours (you can decide when to "start" your time window, after the login). Participation will be available upon registration (re-registration needed for each contest). The problem statements will be available in English only, and the languages officially supported are C, C++, Pascal and Python 3. Every contest will consist of 8 or 9 problems (see https://squadre.olinfo.it and https://iio.team for further information).

For each mirrored rounds you want to participate in, you will have to:

  • Visit the contest website: https://mirror.squadre.olinfo.it/
  • Click the link "Register", fill out the form and confirm (this should be done for each online round since we don’t store the accounts permanently!)
  • You can now log in with the same username and password chosen
  • If the login is successful you will be ready to participate, just wait for the contest to start! (and consider bookmarking the page so that you can quickly get back to it when the contest begins)
  • When the contest starts, you will see a red button: click it when you want to start your 3 hour time window
  • The ranking for each contest will be available at https://mirror.squadre.olinfo.it/ranking/ after the start of each contest
  • Good luck and have fun!

The tasks will also be published for training purposes on https://training.olinfo.it few days after the contests.

The schedule of the contests is the following (starting times in the CET time zone):

  • Practice: nov. 9 to nov. 12
  • Round 1: nov. 15 @ 14:30
  • Round 2: dec. 14 @ 14:30
  • Round 3: jan. 12 @ 14:30
  • Round 4: feb. 3 @ 14:30
  • Finals: feb. 25 @ 13:00

We hope that these online rounds will be an opportunity for your students to train while having fun!

Edoardo Morassutto
(on behalf of the Italian IIOT organizers)

Need more info?


Not sure where to go? Click here to view some basic information on how to learn programming and prepare to win a medal at the IOI.


A couple of volunteers maintain a separate page with stats about people who participated at the International Olympiad in Informatics.


The IOI publishes a journal every year, with original high-quality scientific papers related to education, contests and algorithms.