All problems from day 1 of and day 2 IOI '26 have been added. You may access them here.
An unofficial mirror for day 1 and day 2 of the contest have been set up.
The problem statements and data were uploaded by .
Finally, we wish to congratulate team Canada for their outstanding performance at IOI!
You can see the results here.
This is a follow-up to the previous post on the usage of AI in contests.
As a reminder, all usage of AI on rated contests is prohibited. This includes but is not limited to, ChatGPT and Copilot.
Additionally, the use of DMOJ's judging resources for AI training is prohibited. These models strain DMOJ's judging resources and make the site unusable for average users. As enforcement, we have added a submission rate limit for all users. This is high enough as to not affect legitimate users, while curbing bot abuse.
Furthermore, we reserve the right to terminate bot accounts, and/or poison their training data.
If you wish to use DMOJ's non-judging resources for AI training purposes, such as problem statements or API data, please contact the administrators via email at contact -at- dmoj.ca.
Welcome back everyone! Get ready to kick your school year off with the 2026 edition of the Back to School contest!
The contest will begin on September 9th, 2026 00:00 EST and will last one week. Participants will have a 3-hour window to complete 6 problems.
This contest will be rated for participants with a rating under 2600.
For more information, please visit the contest page.
Good luck and have fun!
DMOJ will be hosting an in-person unofficial mirror of the 2026 Chinese NOI with support from Huawei Canada.
Update: registration has closed.
Welcome to the 3rd iteration of the April Fools' Day Contest.
Here, wrong answers might feel right. Accepted solutions might feel suspicious. Constraints may or may not be trustworthy. Some problems were designed with a punchline in mind, while others got lost between idea and implementation.
Good luck, and may your RTE’s be intentional.
The contest will run from April 1st, 00:00 EDT to April 8th, 00:00 EDT.
All problems will be open for the full duration of the contest. The contest will be unrated, and the scoreboard will be public.
For more information, please visit the contest page.
It's been a while since we've posted an update on what we've been working on, so we felt it was about time for one.
We've updated several runtimes, the big changes being:
We have locked all previous Zig and Scala submissions. If a problem where you have submitted in Zig 0.6 or Scala 2 is rejudged, your submission will no longer count for points.
Aloha all!
After an ambitious and arduous assembly, an Advanced Algorithmic Assessment appears!
The contest will begin on December 18th, 2025 00:00 EST and will last one week. Participants will have a 3 hour window to solve 6 problems.
The contest is rated for participants with a rating less than 2800.
For more information, please visit the contest page.
Awesome activities and amazing adventures await!