DMOPC '15 October Contest

Welcome to the first Don Mills Open Programming Competition of the 2015-2016 school year!

The problem writers this time are cheesecake, Xyene, and FatalEagle.

This round will be rated for all participants.

We are using a new format for the competition this year. The DMOPC will be a 3-hour virtual contest, which will allow contestants to participate in any 3-hour window between 12PM EDT and 9PM EDT. Of course, it is forbidden to use two accounts to participate, and it is also forbidden to discuss the problems and/or their solutions with other people during the entire contest period.

Another change is that system tests will be run after the contest period ends, as an additional measure to prevent cheating. During the contest, on problems 4, 5, and 6, when you submit, you will receive your result on some of the test data, called preliminary tests (pretests). If you pass all the pretests, you will get a (temporary) score of 1/1 for that problem. After the contest, we will rejudge all solutions on the complete set of test data, and that will determine your final score, out of 100, as usual. Note that getting AC on pretests does not necessarily ensure you will pass system testing.

It's guaranteed that all subtasks will show up at least once in the pretest.

You will not be able to view partial output during the contest.

The theme for this month's contest is GATE.

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. 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 EDT), 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!

Problems

Problem Points AC Rate Users Editorials
DMOPC '15 Contest 1 P1 - Itami and Manga 3p 48.3% 697 Editorial
DMOPC '15 Contest 1 P2 - Itami and Squad 5p 33.8% 267 Editorial
DMOPC '15 Contest 1 P3 - Itami and Cipher 7p 28.2% 191 Editorial
DMOPC '15 Contest 1 P4 - Itami and Candy 10p 27.6% 247 Editorial
DMOPC '15 Contest 1 P5 - Lelei and Dragon Scales 10p 20.2% 427 Editorial
DMOPC '15 Contest 1 P6 - Lelei and Contest 17p 18.9% 401 Editorial

Comments


  • 0
    admin  commented on Oct. 14, 2015, 3:12 a.m. ← edit 2

    Final standings are up. Reply if you have any concerns.


  • -1
    bobhob314  commented on Oct. 14, 2015, 1:30 a.m.

    f


    • 0
      Xyene  commented on Oct. 14, 2015, 2:32 a.m.

      It's currently undergoing system testing.


  • 1
    Jeffrey  commented on Oct. 14, 2015, 1:17 a.m.

    I did not participate in the contest but can I still view the contest problems?


    • -1
      bobhob314  commented on Oct. 14, 2015, 1:23 a.m.

      Yes, after the contest ends.


  • 0
    pyrexshorts  commented on Oct. 13, 2015, 10:59 p.m.

    During rejudging, which submission does the judge take, the best one or the newest one? Thanks.


    • 1
      FatalEagle  commented on Oct. 13, 2015, 11:00 p.m.

      The best submission, and it breaks ties by the last submit time.


  • -1
    bobhob314  commented on Oct. 13, 2015, 10:39 p.m. ← edited

    Hey Tim, Tudor, and cake of cheese,

    Would you mind extending the contest ending slightly, to 10PM? This would be greatly appreciated.

    Warm regards,

    Max


  • 1
    pyrexshorts  commented on Sept. 25, 2015, 2:33 a.m.

    Why is the grading system different than CCC? Isn't the point of DMOPC to practice for CCC?


    • 3
      FatalEagle  commented on Sept. 25, 2015, 2:54 a.m.

      You can think of this as old-style CCC, where you had one submission and only the samples to test on.

      Also, in the real CCC, you would skip school to do it. Since we do not have the luxury of skipping school to do the DMOPC, this system must be adopted.


      • 2
        pyrexshorts  commented on Sept. 25, 2015, 3:02 a.m.

        Can you elaborate on the last bit?


        • 3
          FatalEagle  commented on Sept. 25, 2015, 3:05 a.m. ← edited

          In the CCC, you write it during the school day under teacher supervision to make sure you don't cheat. We have no way to enforce this rule at DMOPC, and in an attempt to keep the scores as accurate as possible we delay final judgement until after the contest.

          Additionally, you can practice for CCC with something that isn't exactly like the CCC. For example, you may have been solving problems on online judges - with no time limit, immediate feedback, sometimes even input/output data, etc. During the CCC you will have a time limit, no feedback for the first few hours, a terrible results page you have to F5 constantly, and misleading verdicts like "Completed". If that sounds like your thing, you can go ahead and practice at https://cccgrader.com/


  • -1
    kobortor  commented on Sept. 25, 2015, 1:50 a.m. ← edited

    Another change is that system tests will be run AFTER the contest period ends, as an additional measure to prevent cheating. During the contest, when you submit, you will receive your result on SOME of the test data, called preliminary tests (pretests). After the contest, we will rejudge all the solutions on the complete set of test data, and that will be your final score. Note that getting AC on pretests do not necessarily mean that you will pass system tests.

    So there is the possibility of the judge showing 100 AC but only to find WA later on?


    • 1
      Xyene  commented on Sept. 25, 2015, 1:56 a.m.

      Indeed, you may find an AC turn into a WA (or IR, etc.) after system testing. Such excitement!


      • 0
        kobortor  commented on Sept. 25, 2015, 2:05 a.m.

        Will the extra cases contain edge or corner cases not included in the normal problemset?


        • 0
          Xyene  commented on Sept. 25, 2015, 2:10 a.m. ← edited

          Naturally.

          Note, though, that all subtasks will appear at least once in the pretests (no frustrating sizing issues, etc.), and the system tests will be the identical to the pretests for the first few problems — the tests will only differ on the harder problems.


          • 0
            kobortor  commented on Sept. 25, 2015, 2:48 a.m.

            Then after the post-contest grading, does the judge take the best from the new batch or the best of the old one?


            • 0
              Xyene  commented on Sept. 25, 2015, 2:56 a.m. ← edited

              You can think of system testing as rejudging with stronger test data. Your initial score will be completely overwritten for all cases by the system test data, and should only serve as an indicator that your solution may be correct (as opposed to definitely incorrect.)


            • 0
              FatalEagle  commented on Sept. 25, 2015, 2:56 a.m.

              The old results are discarded and the new results are final, just like old USACO style. Some pretests will be worth actual points, so if you pass all pretests your score will hopefully be nonzero.


  • -6
    bobhob314  commented on Sept. 25, 2015, 1:48 a.m. ← edit 2

    This comment is hidden due to too much negative feedback. Show it anyway.


    • 0
      gah111  commented on Sept. 25, 2015, 5:25 p.m.

      8/8 wld r8 gr8.