New Year's 2018

It's almost 2018! A new year means setting New Year's resolutions, bettering yourself, and of course — a contest!

The problem writers this time will be Kirito, r3mark, and Eliden.

The New Year's Contest will be a 5-hour virtual contest. which will allow contestants to participate in any 5-hour window between 9 AM EST, January 1, 2018 and 9 PM EST, January 2, 2018. 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.

The pretest/systest format will not be used. This means that submissions will be judged on the full set of data during the contest. However, partial output will be disabled.

This contest will be rated for all participants who submit at least once.

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

The contest will run from Jan 1, 9 AM EST to Jan 2, 9 PM EST. It will consist of 8 problems in approximated increasing order of difficulty. The problems will be allotted different point values based on their difficulties.

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. Your last submission time 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.

Good luck and Happy New Year!


  • 7
    Evan_Yu123  commented on Jan. 2, 2018, 9:58 p.m.

    lol the rating market just crashed...

  • 0
    AngusRitossa  commented on Jan. 1, 2018, 11:30 p.m.

    For problem 8, subtask 3 data is weak (my code that should've been too slow got TLE on sub 1 & 2 and AC on sub 3)

    • -1
      r3mark  commented on Jan. 2, 2018, 11:27 p.m.

      Stronger data for P8 has been uploaded. As this contest is not systested, your submission will not be rejudged against the new data.

    • -1
      r3mark  commented on Jan. 2, 2018, 1:23 a.m.


  • 7
    Chensta  commented on Jan. 1, 2018, 7:02 p.m.

    TIL that Bob has snowmen that can be two times taller than the distance between the Sun and Jupiter.

    • 6
      r3mark  commented on Jan. 1, 2018, 7:22 p.m.

      Fear them.

  • 1
    r3mark  commented on Jan. 1, 2018, 3:19 p.m.

    For problem 1, there has been an update in the problem statement, specifically in the output specifications. This was made due to an error in the problemsetter's official solution, but the test cases themselves will not change (e.g. we are keeping the incorrect data).

    Apologies to xyz2606 for being incorrectly informed after pointing this error out and anyone else who was affected by this error.

    • 0
      Kirito  commented on Jan. 1, 2018, 3:26 p.m.

      Additionally, azneye found that there was some trailing input in P6, specifically in subtask 3 cases 17 and 18. The test cases have been updated, and all affected solutions have been rejudged.

      Apologies to any users who were affected by this error, and azneye in particular.

  • -1
    1021839  commented on Jan. 1, 2018, 10:25 a.m. edited

    For the seventh problem, is there a limit on the length of the string at a particular node?

    • -1
      r3mark  commented on Jan. 1, 2018, 2:45 p.m. edited

      Sorry for the late response, but the lengths are at least 1 and the sum of the lengths is S. Other than that, there are no constraints on any individual lengths.

  • 4
    xyz2606  commented on Jan. 1, 2018, 9:07 a.m.

    I think the first hidden case of the first problem is wrong. You can see my last two codes for that problem.

  • 7
    Kirito  commented on Dec. 30, 2017, 11:52 p.m.

    By popular request, the contest has been extended to a 5-hour virtual contest, meaning that you can write this contest in any 5-hour period from 9 AM EST, January 1, 2018 to 9 PM EST, January 2, 2018.

    • 3
      wleung_bvg  commented on Dec. 31, 2017, 1:13 a.m.

      Are ties still broken by the submission time from the start of the contest (9am on Jan 1)? Or is it based on the submission time from each individual's start time?

      • 3
        r3mark  commented on Dec. 31, 2017, 3:02 a.m.

        Individual start time

        • 2
          wleung_bvg  commented on Dec. 31, 2017, 5:31 a.m.

          So the statement (from the description above)

          It is also highly recommended that you join and start the contest as soon as possible since ties are broken by your submission times.

          is no longer accurate and starting at a later time will not put us at a disadvantage?

          • 1
            Kirito  commented on Dec. 31, 2017, 7:15 a.m.

            Fixed; sorry about that, there were a few communication errors along the way.

  • 8
    TheZombieCloud  commented on Dec. 30, 2017, 7:59 p.m.

    Can this contest be extended by a day?

    • 0
      Evan_Yu123  commented on Jan. 1, 2018, 9:36 a.m. edited

      Request from TheZombieCloud (he can't access dmoj rn): can this contest be extended further to end on 23:59 January 2?

    • 10
      KevinLu  commented on Dec. 30, 2017, 9:42 p.m.

      I am also requesting this, as I (and possibly other users) have responsibilities on New Year's Day.