COCI Logo
 
CROATIAN OPEN COMPETITION IN INFORMATICS
 
Internet online contest series
 
Over the next six months we will organize seven online contests as a warm-up for the 2026 season of high school programming competitions. Everyone is welcome to participate!
 
Each contest will be three hours long and will feature five tasks. The contestants will also have full feedback with at most 50 submissions per task. The tasks will be of widely varying difficulty; we hope that many beginner or up-and-coming contestants will participate, as well as the more experienced ones.
 
The first contest will be held on Saturday, October 25, starting at 14:00 (GMT/UTC). You may use Python, Pascal, C/C++ or Java as your programming language of choice.
 
Instructions, problems and the contest system will be located at
https://evaluator.hsin.hr
 
You can find problems, test data and solutions from previous Croatian competitions in informatics in the COCI 2006/2007 Archive, COCI 2007/2008 Archive, COCI 2008/2009 Archive, COCI 2009/2010 Archive, COCI 2010/2011 Archive, COCI 2011/2012 Archive, COCI 2012/2013 Archive, COCI 2013/2014 Archive, COCI 2014/2015 Archive, COCI 2015/2016 Archive, COCI 2016/2017 Archive, COCI 2017/2018 Archive, COCI 2018/2019 Archive, COCI 2019/2020 Archive, COCI 2020/2021 Archive, COCI 2021/2022 Archive, COCI 2022/2023 Archive, COCI 2023/2024 Archive, COCI 2025/2025 Archive and here.
 
Feel free to e-mail us at for any and all additional information.
 
Scientific Committee
 
Jakov Celin, chairperson
 
Vito Anić
Fran Babić
Toni Brajko
Nikola Dmitrović
Ivan Jambrešić
Ivan Janjić
Josip Klepec
Martina Licul
Petar Sruk
Iva Tadić
 
Evaluation and Technical Committee
 
Matej Ferenčević
 
Project Manager
 
Krešimir Malnar