DMOPC '14 December Contest

Welcome to the third Don Mills Open Programming Competition of the year! In this month's contest, you'll be helping Amagi Brilliant Contests.

Amagi Brilliant Contests runs a business making and hosting contests on its online platform for competitive programmers who want to run their own contests.

The problem writers this time are FatalEagle and Xyene.

Update 3: Thanks to everyone who participated in the DMOPC December! The contest is now over.
The solutions can be found here.

Update 2: If you have any clarification requests, either post them in chat or send them to dmcioj (at) gmail (dot) com.

Update: There are six problems. The names of the problems are:

1. Not Enough Users!
2. Not Enough Rejudging!
3. Not Enough Personnel!
4. Not Enough Testers!
5. Not Enough Servers!
6. Not Enough Time!

Before the contest date, you may wish to check out the tips and help pages.

The contest consists of 6 questions with a wide range of difficulties, and you can get partial marks for partial solutions in the form of subtasks. If you cannot solve a problem fully, we encourage you to go for these partial marks. The difficulty of a problem may be anywhere from CCC Junior to CCO level. You will have 3 hours to complete the contest. Check when the contest begins in your timezone here.

After joining the contest, you proceed to the Problems tab to begin. You can also go to Users if you wish to see the rankings.

We have listed below some advice as well as contest strategies:

  • Start from the beginning. Ties will be broken by the sum of times used to solve the problems starting from the beginning of the contest. The first 3 problems are ordered by difficulty. The last 3 problems are not necessarily in order of difficulty, so read all the problems first.
  • It is strongly advised to run your code on your own computer with the sample input we provide before submitting. It's faster to find and fix mistakes at this stage rather than submitting and waiting only to find out that your solution doesn't compile.
  • Remove all extra debugging code and/or input prompts from your code before submitting. The judge is very strict — it requires your output to match exactly.
  • Do not pause program execution at the end. The judging process is automated. You should use stdin / stdout to perform input / output, respectively.
  • Ensure your program works with the sample input, however, just because it works with the sample input doesn’t guarantee that it will earn full points. Read the problem statement very carefully to look for things you may have missed on the first read-through. It is not forbidden — in fact, even encouraged to make your own test cases to debug your program on.
  • If you’re stuck on a problem, or are getting most of the partial marks, you can simply proceed to the next question. There are some people who spend their time debugging or making their code more efficient only to earn a few extra points for one question. Sometimes it's best to just move on and return to that question later on in the contest.
  • The test data is guaranteed to fit within the constraints given. You do not have to perform any extra checks to make sure of this fact.
  • It is guaranteed that all the problems will be solvable with C++. Languages slower than C++ are guaranteed to be able to solve at least 4 problems.

At the end of the contest, you may comment below to appeal a judging verdict. In the case of appeals, the decision(s) of DMOJ staff is final. We also reserve the right to add additional test cases to the problems after the contest, if extremely wrong solutions are incorrectly judged as AC. We will make an announcement in-contest if we plan to add more test cases.

After the contest finishes, we'll have a optional feedback form we would like you to fill out.

Good luck!


  • 3
    echibrat  commented on Dec. 15, 2014, 10:21 p.m.

    Omg amagi brilliant park...

  • 1
    snowblind  commented on Dec. 14, 2014, 12:07 p.m.

    nice meme