All problems from this year's CCC have been added. You may access them here.
Editorials for most problems can be found on their respective pages — please remember to use these editorials only when stuck, as copy-pasting code from them will see you permanently banned from submitting that problem.
Hope you enjoyed this year's CCC!
Thanks for participating in the DMOPC '17 February contest!
The winners are:
Editorials for each of the problems are in the process of being uploaded to the respective problem pages.
We hope you enjoyed the contest, and see you next month!
On Tuesday, February 20th, we'll be hosting the February Don Mills 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 noon EST of Feb. 20th and noon EST of Feb. 21th. Please see the contest page for more details.
See you soon!
We welcome you to this year's Valentine's Day Contest!
Unfortunately, due to the date of the Canadian Computing Contest being on the 14th, the Valentine's Day Contest will be running on the 11th of February. This contest will have cuteness and love themed problems to help contestants enjoy this celebration of love. Because the CCC is coming up, the Valentine's Day Contest will be in CCC format, with two divisions, with five problems each to solve in 3 hours. The window will open at 9AM EST on the 11th and will run till midnight.
We'll be running both junior and senior divisions.
Problem setters for this contest are , and .
The CCC is rapidly approaching, and so it's time for this year's Richmond Green Programming Contest to help you prepare!
The RGPC '18 will be a 3-hour virtual contest, which will allow contestants to participate in any 3-hour window from 12:00 AM EST, February 10, 2018 to 12:00 AM EST, February 12, 2018. Please see the contest page for more details.
Good luck on both the RGPC and the CCC!
We're excited to invite you to participate in a series of contests that will emulate the Canadian Computing Competition! These contests are being produced by , , , and with the intended audience being any student who wishes to practice for the CCC.
All of these contests will be similar in format to the CCC — there will be a junior division and senior division with problems spanning the difficulty of the CCC. All of these contests are unrated.
The first contest will go live on January 29th, 2018 and be open for 72 hours. As with the regular CCC, the contest will be a 3-hour virtual contest which will allow contestants to participate in any 3-hour window for those three days.
We will be producing a set of five such contests from now until CCC. We wish everyone writing the CCC good luck on our contests and on the CCC!
Thanks for participating in the TLE '17 January contest!
The winners are:
Editorials for each of the problems will be uploaded to the respective problem pages.
We hope you enjoyed the contest, and see you next month!
We're excited to invite you to the fifth Thorndeau Logic Evaluation of the 2017-18 school year!
The problem writers/testers of this round are , , , and .
Note that this will be the last TLE before the Canadian Computing Competition, so give it your all!
The TLE '17 January contest will be a 3-hour virtual contest, which will allow contestants to participate in any 3-hour window from 12:00 PM EST, January 26, 2018 to 12:00 PM EST, January 27, 2018. Please see the contest page for more details.
See you soon!
Thanks to everyone who participated in the New Year's Contest! We hope that you enjoyed the contest! Congratulations to the winners:
Editorials have been uploaded to their respective problem pages.
Happy New Year!
We hope everyone's been enjoying their winter break because it's about to get better!
On January 1, we will be hosting DMOJ's own New Year's 2018 contest. Please see the contest page for details.
Anyone with a DMOJ account is welcome to participate, and anyone without one is welcome to register and participate.
See you soon, good luck, and Happy Holidays from all of the DMOJ crew!
Thanks for participating in the TLE '17 December contest!
The winners are:
Editorials for each of the problems will be uploaded to the respective problem pages.
We hope you enjoyed the contest, and see you next month!
We're excited to invite you to the fourth Thorndeau Logic Evaluation of the 2017-18 school year!
The TLE '17 December contest will be a 3-hour virtual contest, which will allow contestants to participate in any 3-hour window from 12:00 PM EST, December 22, 2017 to 12:00 PM EST, December 23, 2017. Please see the contest page for more details.
See you soon!
Thanks for participating in the DMOPC '17 December contest!
The winners are:
Editorials for each of the problems have been uploaded to the respective problem pages.
We hope you enjoyed the contest, and see you next month!
On Tuesday, December 12th, we'll be hosting the December Don Mills 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 noon EST of Dec. 12th and noon EST of Dec. 13th. Please see the contest page for more details.
See you soon!
Over the past few weeks, we've been hard at work improving DMOJ's backend for a better user experience, and today we've finally made these changes live.
The servers backing DMOJ have not received upgrades in years, and were constantly dangerously close to hitting CPU and memory limits.
After some particularly successful Black Friday shopping, we're happy to announce we've doubled the resources available to our frontend servers, and octupled those of our database. We've also split up several other services onto smaller machines dedicated to running them. Judging servers have not been updated, so expect no change in submission runtimes.
All servers have also been migrated from a New York datacenter to one in Montréal, so Canadian users should experience improved connectivity (international accesses should not be affected significantly). In our tests, the new servers render pages 20-40% faster than the old ones, and leave a lot of room for increased load during peak times.
Since this required massive changes to our networking setup behind-the-scenes, it's possible that there might be slight issues in the next few days.
We've heard reports of DMOJ links being blocked on Facebook and Messenger, and have taken steps to resolve this. Previously, resources were being served off of dmoj.ml (for site resources) and camo.dmuser.ml (for SSL-proxied user content) — as of recently, Facebook blocks sites linking .ml TLD domains. As a result, we now serve off of dmoj.algome.me and camo.algome.me, respectively. If you use NoScript, uMatrix, or similar script-blocking browser plugins, you will have to allow these domains to use DMOJ.
Facebook issues should clear up within a few days.
The judge has seen a lot of work recently, largely for improving stability. Among others,
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