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Due to COVID-19, IOI 2021 was hosted by Singapore online. Visit the official website to learn more.

Just finished   IOI 2021 was held online

JOI Open Contest 2021

Dear all,

JOI Open Contest 2021 is an IOI-like open competition for students at schools for secondary education. The main purpose of this contest is to give Japanese delegations and candidates of delegations an opportunity for training and practice. But the contest itself is open to everybody. Everybody is welcome to attend JOI Open Contest 2021!

This year, the contest will be held on Sunday, June 6, 2021. There will be 3 tasks. Each submitted source program must be written in C++ (C++17).

Problem statements will be provided both in Japanese and English.

The duration of the contest is 5 hours. The contest server will be open during Sunday, June 6, 2021 04:00 - Monday, June 7, 2021 04:00 (UTC/GMT). Contestants can choose start time from above freely. After the contest finishes, we will open the judging server for one week. Interested contestants can improve and resubmit their solutions by themselves. After the contest finishes, we will fix the standings. No prizes will be given to the contestants.

Contest website:

Contest duration: 5 hours
The number of tasks: 3 tasks
Language: English, Japanese
Programming Language: C++ (C++17)
Details will be announced on the contest website.

Date & Time:
  Sunday, June 6, 2021 13:00 - Monday, June 7, 2021 13:00 +0900 (JST)
  Sunday, June 6, 2021 04:00 - Monday, June 7, 2021 04:00 (UTC/GMT)

Judging Server is open until
  Monday, June 14, 2021
  13:00 +0900 (JST)
  04:00 (UTC/GMT)


Executive director of the Japanese Committee for the IOI
Seiichi Tani
Chairperson of the Scientific Committee of JCIOI

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.


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