Olympiads

Author: Benjamin Qi

Once you've reached Platinum, it may be helpful to practice with problems from other (inter)national Olympiads.

Hello, Which online judge should I practice more to do well in IOI?

oj.uz is a great online judge that has most of the Olympiad problems that you'll probably want to solve. However, other great online judges with different Olympiad problems exist. Also, the OI Checklist is a great way to track your progress.

Here is a list of major (inter)national Olympiads and the online judges where you can solve problems from them. See the IOI members page for additional links.

IOI (International Olympiad in Informatics)

Resources
IOItopics that can and cannot appear on IOI
  • oj.uz
    • All problems from 2007-2019 and Reverse from 2003.
  • Yandex
    • All problems from 2003-2018.
    • More lenient time/memory limits.
  • DMOJ
    • Some problems from 1994-2019.

North America

USACO

CCC / CCO (Canada)

  • DMOJ
    • Most problems from 2000-2020.

Europe

Baltic OI

  • CSES
    • All problems from 2005-2020.
    • Supports virtual contests (great for practice).
  • oj.uz
    • Most problems from 2011-2020.

CEOI (Central European)

  • CSES
    • All problems from 2005-2019.
    • Supports virtual contests (great for practice).
  • oj.uz
    • Most problems from 2006-2019.

COI / COCI (Croatian)

  • DMOJ
    • Most problems from 2006-2019.
  • oj.uz
    • All problems from 2014-2019.

POI (Polish)

Warning!

Solutions from POI problems are unfortunately only available in Polish.

LMIO (Lithuanian)

  • oj.uz
    • Most problems from 2017-2019.

Other

Asia

JOI (Japanese)

  • oj.uz
    • Most problems from 2013-2020.
    • Some statements are only available in Japanese.

APIO (Asia-Pacific)

  • oj.uz
    • Most problems from 2013-2019.

IZhO (Kazakh)

  • oj.uz
    • All problems from 2011-2014 and 2017-2019.

Other

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