DMOJ is hosting An Unrated Contest, a fun contest running for a week. As the name suggests, it is unrated, though it contains normal problems. The problems are just not quite fit for a rated contest.
You can check out more details on the contest page.
Have fun!
DMOJ's rating system was based off of Topcoder's rating system, using rating and volatility to rank contestants. Topcoder's rating system has a flaw that contestants who wish to maximize their rating have incentives to underperform in contests to increase their volatility, as higher volatility leads to larger rating changes. For similar reasons to the above, contestants' ratings do not converge quickly to their true rating. Due to these flaws in the current rating system, DMOJ has moved to a new rating system called Elo-MMR.
Elo-MMR is a rating system designed by Aram Ebtekar and Paul Liu. It's designed to be used in formats where multiple contestants compete in rated competitions at the same time and can be ranked discretely against each other. It is designed to converge contestants' ratings more quickly than existing rating systems. Furthermore, contestants wishing to maximize their rating are never incentivized to underperform in any competition.
Because of the migration, user ratings have been retroactively changed as if DMOJ had always been using Elo-MMR. On average, users' ratings will have increased slightly, so rating cutoffs for titles have been increased accordingly. The new rating title boundaries look like this:
| Title | Old Range | New Range |
|---|---|---|
| Newbie | <1000 | <1000 |
| Amateur | 1000-1199 | 1000-1299 |
| Expert | 1200-1499 | 1300-1599 |
| Candidate Master | 1500-1799 | 1600-1899 |
| Master | 1800-2199 | 1900-2399 |
| Grandmaster | 2200-2999 | 2400-2999 |
| Target | ≥3000 | ≥3000 |
The rating distribution on DMOJ looks as follows:
For further technical details on exactly how Elo-MMR works, please refer to this paper.
Hi everyone!
From Saturday, July 31st to Wednesday, August 4th, we'll be hosting An Animal Contest 3. Participants will have a 3-hour window to complete 8 problems centered around monkeys! See the contest page for more details.
Note that unlike AAC2, AAC3 is rated for everyone.
We hope you enjoy the problems and have fun!
See you soon!
Hi everyone!
July 17th is World Emoji Day. On most platforms, the calendar emoji 📅 shows this date. Naturally, to celebrate this day, we'll be hosting a week-long contest about calendars. See the contest page for more details.
We hope you enjoy the problems and have fun!
See you soon!
Note: the contest has been extended to July 27th
From Saturday, July 24th to Tuesday, July 27th, we'll be hosting CPC '21 Contest 1!
The contest will feature 7 main problems, along with a P0, and will run for 3 hours. You can find more details on the contest page.
Good luck!
Thanks for participating in the Canada Day '21 Contest!
Congratulations to the top 5 contestants!
From Friday, July 2nd to Tuesday, July 6th, we'll be hosting the Canada Day '21 Contest!
Anyone with a DMOJ account is welcome to participate, and anyone without one is welcome to register and participate.
Contestants may participate in any 2-hour window between 00:00:00 EDT of July 2nd and 00:00:00 EDT of July 6st. Please see the contest page for more details.
Good luck!
Hi, everyone!
From Monday, June 21st to Monday, June 28th we'll be hosting the Bayview Secondary School 2021 Junior Programming Contest! This contest is a culmination of what Bayview Computer Club has learned over the past year. Unfortunately, the senior contest will be hosted at a later date. Participants will have a 3-hour window to complete 6 problems. See the contest page for more details.
We hope you enjoy the problems and have fun!
Thanks for participating in the DMOPC '20 June Contest!
Congratulations to the top 5 contestants!
We hope you enjoyed the contest! We'll see you next year for DMOPC '21!
From Saturday, June 19th to Monday, June 21st, we'll be hosting the June DMOJ Monthly Open Programming Contest!
Anyone with a DMOJ account is welcome to participate, and anyone without one is welcome to register and participate.
Contestants may participate in any 3-hour window between 00:00:00 EDT of June 19th and 00:00:00 EDT of June 21st. Please see the contest page for more details.
See you soon!
Thanks for participating in the DMOPC '20 May Contest!
Congratulations to the top 5 contestants!
See you next month!
From Saturday, May 29th to Monday, May 31st, we'll be hosting the May DMOJ Monthly Open Programming Contest!
Anyone with a DMOJ account is welcome to participate, and anyone without one is welcome to register and participate.
Contestants may participate in any 3-hour window between 00:00:00 EDT of May 29th and 00:00:00 EDT of May 31st. Please see the contest page for more details.
See you soon!
Hi, everyone!
From Saturday, May 22nd to Monday, May 24th we'll be hosting the first (and hopefully last) ever Quarantine Computing Contest! This contest features the very contagious COVID-19. Participants will have a 2.5-hour window to complete 7 problems. See the contest page for more details.
We hope you enjoy the problems and have fun!
Stay safe and see you soon!