Dear Codeforces community,

The Asia-Pacific Informatics Olympiad (APIO) 2021 is going to take place this month.

We invite everyone to participate in the APIO 2021 Open Contest. The open contest will have the same problemset as APIO 2021 and will be held using CMS. The open contest will be held between Monday, 24 May 2021 (05:00 UTC+0) and Wednesday, 26 May 2021 (05:00 UTC+0). The duration of the contest is 5 hours, and you can participate at any time within that window.

More details are available on https://apio2021.id/open.html. You can register and access the contest on https://open.apio2021.toki.id/.

We wish everyone to enjoy the open contest!

Thanks,
APIO 2021 Scientific Committee

UPD: The practice session is just over. The problems used are coming from Indonesia's past contests:

• Problem cards: https://tlx.toki.id/problems/tsoc-cms/B
• Problem defence: https://tlx.toki.id/problems/ksn-2020/1A
• Problem hoax: https://tlx.toki.id/problems/osn-2019/2C

You may upsolve the problems there. Some of them have editorials that can be found from the left side of the page.

Feel free to join our virtual opening ceremony on Youtube today, and do not forget to register for the open contest!

UPD: The main competition has just ended, and the open contest has just started! We encourage APIO 2021 participants to NOT discuss the competition until the open contest has ended.

Please take note that not all countries are listed when you registered for a new user. This is because the initial list was taken from countries that participated in IOI before. If you would like more representation countries to be added to the list, please contact info.apio2021@toki.id

Good luck with the open contest!

UPD: The open contest has ended! You may now discuss about the competition tasks. Feel free to join the virtual closing ceremony and medal awarding streamed on Youtube soon. The open contest result will soon be published after the ceremony has ended.

UPD: APIO 2021 has officially ended!

• The result for the main competition can be found here.
• The result for the open contest can be found here.
• You can upsolve the problems here.
• The editorial can be found here.

Congratulations to all the medalists!