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If this is your first visit, please register an account. Then, try the Hello, World! problem.



Don Mills Programming Gala 2016

April 15, 2016, 12:49

As the academic year comes to an end, we'll be holding our final DMOPC in the form of the Don Mills Programming Gala, which will take place at Don Mills C.I. on Wednesday, May 18th.

The contest will be split into three divisions of increasing difficulty, with prizes awarded to the top competitors. For interested competitors unable to attend the on-site event, we will also be hosting mirrors of the divisions, open for anyone to participate in.

Space is limited, so sign up soon! More details and registration options may be found here. You can find results and photos from last year's DMPG here.

Registration is now closed.

TSOC '16 #2

April 15, 2016, 23:16

Thanks to everyone who participated in this year's April 20 contest!

Congratulations to the top three contestants:

  1. d
  2. r3mark
  3. ZQFMGB12

We hope you enjoyed the contest! If you have any suggestions or wish to contact the problemsetters, you may reach them via tsscomputerclub@gmail.com.


The fabled April 20 Contest, 2016 will be open starting April 20th!

From Wednesday, April 20th to Sunday, April 24th, challenge your friends and dastardly foes in the battle royale of a lifetime – the competition of mythical proportions known only as the April 20 Contest, brought to you by your pals at Thornhill.

Contestants may participate in any 3-hour window between 1 AM EST on the 20th and 11PM EST on the 24th. Anyone with a DMOJ account is welcome to participate, so register for an account if you haven't already. Please see the contest page for more details.

DMOPC '15 April Contest

April 2, 2016, 23:47

Thanks to everyone who participated in this month's DMOPC!

Congratulations to the winners:

  1. Deemo (perfect score)
  2. d
  3. alei
  4. grikukan
  5. Mariya

We hope you enjoyed the contest! Stay tuned for news on DMPG - the final contest of the year which will be onsite!


On Tuesday, April 12th, we'll be hosting the April 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 12PM EST and 12AM EST. Please see the contest page for more details.

See you soon, and good luck!

TLE '16

March 15, 2016, 22:10

Thanks to everyone who participated in TLE '16!

Congratulations to the winners:

  1. Butane
  2. r3mark
  3. jeffreyxiao
  4. arock
  5. gongy

Editorials will be available on the respective problem pages. We hope you enjoyed the contest!

DMOPC '15 March Contest

Feb. 23, 2016, 16:14

Thanks to everyone who participated in this month's DMOPC!

Congratulations to the winners:

  1. d (perfect score)
  2. Butane
  3. bruce
  4. kobortor
  5. ZQFMGB12

We hope you enjoyed the contest! See you next month!


On Tuesday, March 1st, we'll be hosting the March Don Mills Open Programming Contest! Important note: this is one week before the standard date, due to the CCOQR taking place on March 8th.

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 12PM EST and 9PM EST. Please see the contest page for more details.

See you soon, and good luck!

CCC 2016 Problems

Feb. 20, 2016, 1:40

We have added all CCC 2016 problems to the Don Mills Online Judge.

You may find them here: http://www.dmoj.ca/problems/?search=%22ccc+%2716%22.

DMOPC '15 February Contest

Jan. 28, 2016, 12:37

Thanks to everyone who participated in this month's DMOPC!

Congratulations to the winners:

  1. alei
  2. ZQFMGB12
  3. d
  4. Butane
  5. grikukan

We hope you enjoyed the contest! All problems have been moved to the main judge, and editorials may be found on the problem pages by clicking "Read editorial". See you next month!


On Tuesday, February 9, 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 12PM EST and 9PM EST. Please see the contest page for more details.

See you soon, and good luck!

DMOPC '15 January Contest

Jan. 11, 2016, 14:50

Thanks to everyone who participated in this month's DMOPC!

Congratulations to the winners:

  1. gendelpiekel (perfect score)
  2. jeffreyxiao (perfect score)
  3. d (perfect score)
  4. Quantris (perfect score)
  5. Butane

We hope you enjoyed the contest! Editorials can be found here. See you next month!


The contest was set by members of Cygnus Computer, a competitive programming club based in Bucharest, Romania. Cygnus has contributed to the localization of the site (you may change your language at the bottom of every page), and is now running a Romanian-language version of DMOJ at http://cygnus-computer.ro/arena/. Thanks!


On Tuesday, January 12th, we'll be hosting the January Don Mills Open Programming Contest!

Anyone with a DMOJ account is welcome to participate, and anyone without one is welcome to register and participate.

The problem writers this time are StellarCF, ionutpop118, and WallE256.

Contestants may participate in any 3-hour window between 12PM EST and 9PM EST. Please see the contest page for more details.

See you soon, and good luck!

New Year's Contests

Dec. 26, 2015, 13:05

Thanks to everyone who participated in the New Year's contest.

Congratulations to the winners:

  1. zimpha (Perfect score)
  2. d (Perfect score)
  3. jeffreyxiao (Perfect score)
  4. mehwar (Perfect score)
  5. bruce (Perfect score)
  6. grikukan
  7. Butane
  8. gongy
  9. ZQFMGB12
  10. pyrexshorts

A brief solution sketch can be found here. We hope you enjoyed the problem set and learned something new. Happy new year!


We hope everyone's been enjoying their winter break because it's about to get better!

In the coming week we will be hosting two contests: the Mackenzie New Year's Challenge, and DMOJ's own New Year's 2016 contest. Please see the contest pages 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!

Introducing User Scripts

Dec. 19, 2015, 18:41

With the recent addition of Wikipedia-like user scripts, now you can change how the DMOJ looks and works! A user script is a small bit of customizable Javascript that is embedded into every page, and allows you to modify everything regarding the site's look. User scripts may be defined in the edit profile page.

For example, if you wanted to make the navigation bar non-sticky, you could use a simple script.

// Wait for page load
$(function() {
    // Select the navigation bar
    $("#navigation").css({
        // Update the CSS
        position: "absolute"
    });
});

Or perhaps you'd prefer a more festive look to the site.

$(function() {
    $("#page-container").css({background: "#FDDDDD"});
    $("body").css({background: "#99FFA8"});
});

Or even display an encouraging message on every page load.

$(function() {
    alert("You can do it!");
});