OTHS Coding Competition 4
posted on May 21, 2025, 1:29 a.m. 0
Hi everyone!
This Thursday, we'll be hosting the end-of-school-year OTHS Coding Competition!
The contest will be unrated. For more details, check out the contest page.
Have fun!
News
CCO '25 and CIW '25 Problems Posted
posted on May 31, 2025, 6:11 p.m. 2All problems from this year's CCO and CIW have been added. You may access them here and here, respectively.
Unofficial mirrors for CCO day 1, CCO day 2, CIW day 1, and CIW day 2 have also been set up.
The problem data were uploaded by , the problem statements were uploaded by , and the mirrors were made by .
An unofficial scoreboard for CCO is accessible here compiled by .
Finally, congratulations to , , Alex Lin, and Tarek Ahmed, who will be representing Canada at the IOI!
Rating System Update
posted on April 1, 2025, 10:00 a.m. 1April Fools! Your rating has been reset to zero!
If you've been paying attention to the discussion on the DMOJ Discord recently, you may have been aware that there has been some discontent with new users being able to get rating after participating in a single contest with a rating ceiling intended for / rated users. In response, we've been working on overhauling the rating system, with a particular focus on contests with rating ceilings. At a very high level, ratings should not exceed 400 plus the rating ceiling (naturally, this is unbounded for contests with no rating ceilings).
All users have had their ratings retroactively changed as if DMOJ had always been using this new system. Furthermore, "rating gain caps" were added to contests labelled as "Junior" contests. (More technically, they had performance_ceiling set to 2000).
Finally, rating ceilings have been retroactively removed from all previous contests (as these would no longer make sense with the new ratings). Any users who were originally not rated have been manually excluded from ratings.
The changes in rating are as follows:
For further explanation, including technical details, we recommend checking out the implementation on GitHub, the original Elo-MMR paper, and this brief discussion with the Elo-MMR creator regarding how to handle contests with rating ceilings.
Finally, please reach out, either via the comments section, via email at contact -at- dmoj -dot- ca, via the issue tracker on GitHub, or via the Discord if you have any concerns, or wish to report any issues.
On the Usage of AI in Contests
posted on Dec. 30, 2024, 4:57 a.m. 8Hello everyone,
As you are likely all aware, AI has improved dramatically at programming recently. Starting now, all usage of AI on rated contests is prohibited. This includes but is not limited to, ChatGPT and Copilot.
We thank you for your cooperation.
April Fools' Day Contest 2
posted on March 31, 2025, 8:00 p.m. 0Hi everyone!
We're excited to present the second edition of the April Fools' Day Contest!
The contest will start on April 1st at 0:00 EST and will last one week. Participants will not have a contest window: all 10 problems will be open for the duration of the contest.
Despite the incredible problem quality, the contest will be unrated. For more details, check out the contest page.
Have fun!
Arcadia Computing Contest 2
posted on March 16, 2025, 4:34 a.m. 0
Hello everyone!
The Arcadia High School Coding Club is excited to announce the second edition of the Arcadia Computing Contest! There will be questions, with two hours to solve them. The contest will start on March 19th at 18:15 EDT and will be open for a week.
The contest will be rated for users with a rating under 1900. For more details, check out the contest page.
Good luck and we hope you enjoy the problems!
Dilhan's Computing Contest 1
posted on Feb. 17, 2025, 1:55 a.m. 0Greetings all!
I am pleased to announce my first (rated) DMOJ contest!
The contest will begin on February 18th, 2025 00:00 ET and will last one week. Participants will have a 3-hour window to solve 6 problems.
The contest is rated for all participants.
For more information, please visit the contest page.
Good luck, and have fun!
OTHS Coding Competition 3 (Mock CCC)
posted on Feb. 11, 2025, 3:48 p.m. 0
Hi everyone!
This Thursday, we'll be hosting the third OTHS Coding Competition! The format of this contest will be the same as the CCC.
The contest will be unrated. For more details, check out the contest page.
Have fun!
Dr. Anne Anderson Coding Contest
posted on Feb. 10, 2025, 8:27 p.m. 0Hi everyone!
The Dr. Anne Anderson High School Coding Club is proud to announce the first ever Dr. Anne Anderson Coding Contest!
It will take place from February 11th at 17:10 EST to February 18th at 00:00 EST. Participants will have a 2-hour window to complete 6 problems.
The contest will be rated for participants with a rating under 1800. For more info, take a look at the contest page.
Good luck and have fun!
Yet Another Contest 9
posted on Jan. 6, 2025, 5:42 p.m. 0
Hi everyone!
Yet another time, this is yet another sentence in yet another paragraph in yet another message in yet another blog post with yet another announcement that there is yet another opportunity for yet another Yet Another Contest!
The contest will run from Friday, January 10th to Monday, January 20th. Participants will have a 3-hour window to complete 6 problems.
Note that the contest is not rated for users with at least 2800 rating.
Good luck and have fun!