The fourth round of the IIOT (International Informatics Olympiads in Teams) is starting tomorrow: Thursday, February 4th 2021! In the meanwhile, you can enjoy our teaser below and try to guess the next nine problems from the hints :)

If you missed the first rounds, you can still join in; check this post for further details. The mirror contest will be 3 hours USACO-style, starting from 14:30 in the CEST/CET time zone, and ending 24 hours after that.

We hope that you will join us or encourage your students to do so!

Giorgio Audrito (on behalf of the Italian IIOT organizers)