DMOPC '15 January Contest

Welcome to the fourth Don Mills Open Programming Competition of the 2015-2016 season!

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

This round will be rated for all participants.

Before the contest date, you may wish to check out the tips and help pages. Anyone unfamiliar with the pretest/systest system should read about it here.

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. After the contest window begins, you may begin at any time. Your personal timer will start counting down, and you will be able to submit until 3 hours from when you started, or until the hard deadline (9PM EST), whichever comes first.

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 last submission time of your highest score will be used.
  • Remove all extra debugging code and/or input prompts from your code before submitting. The judge is very strict — most of the time, 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.
  • It is guaranteed that all the problems will be solvable with C++.

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.

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

Good luck!


  • 1
    gongy  commented on Jan. 10, 2016, 10:00 p.m.

    I apologise if this is the wrong place to ask such a question, but I really cannot find the answer and I hope some people see this. What do your username colours mean? They seem unrelated to your DMOJ rating, so I was wondering if they were something else! Thanks :)

    • 3
      Xyene  commented on Jan. 10, 2016, 10:19 p.m. edited

      A red username identifies a developer of the open-source DMOJ software (i.e., a significant and long-term contributor). A purple name identifies a user who has contributed problems over a prolonged period of time (they set contests or keep the problem archive up to date). All other usernames are blue.

      Edit: ninja'd by r3mark. I'd just emphasize the sustained part of the problemsetter role.

    • 2
      r3mark  commented on Jan. 10, 2016, 10:16 p.m.

      Red means admin, purple means a problem writer, and blue is everyone else. If someone is both an admin and a problem writer, the name will show as red. Some people are problem writers, but their names are not purple, I'm assuming that this is because the colours haven't been updated recently or something.

      • 4
        bobhob314  commented on Jan. 11, 2016, 7:51 a.m.

        Also if you post stupid things in comments that might lose you your purple privileges. Not that I'd know anything about that necessarily.

  • 8
    bobhob314  commented on Jan. 9, 2016, 1:22 p.m.

    I'm pretty interested how this contest is going to turn out because for once, there are no red authors for the DMOPC! Hoping for cool and original problems :)

    • 9
      WallE256  commented on Jan. 9, 2016, 4:06 p.m.

      Thanks! The problems are, of course, proofread and solved by our beloved admins. The contest also marks the opening of a Romanian clone of DMOJ (more details on the contest date), as well as initial efforts to localize the site.

      • 0
        JeffreyZ  commented on Jan. 12, 2016, 4:13 p.m.

        Romanian clone?

        • 1
          WallE256  commented on Jan. 12, 2016, 4:39 p.m.

          We will be using the same software, but different content overall.

      • 2
        MathBunny123  commented on Jan. 12, 2016, 2:39 p.m.

        Cool! Btw I'm Romanian too