DMOPC '15 January Contest

posted on Jan. 11, 2016, 2:50 p.m.

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 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!


  • 1
    Zander  commented on Jan. 12, 2016, 10:35 p.m. edit 2

    Was there a space before the A or something on some of the test cases?

    Edit: To clarify, I got 60/100 using a normal BufferedReader and 100/100 using StringTokenizer

    • 0
      Xyene  commented on Jan. 12, 2016, 10:45 p.m.

      You are right; there was a space at the end of the A value in two cases. I've rejudged P6 solutions and rerated the contest, and you appear to have been the only one affected. Enjoy the ranking increase!

      • 1
        Zander  commented on Jan. 12, 2016, 10:46 p.m. edited

        oh lol thanks :)

  • 0
    r3mark  commented on Jan. 12, 2016, 10:21 p.m. edited

    Originally, my submissions for P4 and P6 were AC, but at around 10:00, the submissions were TLE and WA. Which are the correct results?

    • 3
      Xyene  commented on Jan. 12, 2016, 10:28 p.m. edited

      From 9:00 to just now, we were running system tests. I double-checked your submissions just in case, though.

      Your P4 has an incorrect complexity for the a/b queries: the correct complexity for a query should be \mathcal{O}(log(N)).

    • 2
      jeffreyxiao  commented on Jan. 12, 2016, 10:25 p.m.

      For P4, P5, and P6, there are additional hidden tests after the contest is finished.

      • 2
        r3mark  commented on Jan. 12, 2016, 11:47 p.m.

        Admittedly, the fact that there were only two test cases should have tipped me off.

      • 0
        r3mark  commented on Jan. 12, 2016, 10:28 p.m.

        Is this something that normally happens on contests?