Riolku's Mock CCC

Welcome to Riolku's Mock CCC!

With the CCC right around the corner, Riolku decided to make a contest to test out your skills! Contest setting is hard though, so he roped in Plasmatic to help him set.

Special thanks to AQT, maxcruickshanks, noYou, and wleung_bvg for testing, feedback, and assistance with the problems!

The contest will run from February 13th, 00:00 EST to February 15th 23:59 EST. You will have a three hour window to solve 5 problems of roughly increasing difficulty ranging from CCC Senior Problem 1 to CCC Senior Problem 5.

Here are the parameters of the contest:

  • Contest duration: 3 hours.
  • Number of problems: 5, full feedback. Each problem will be worth 15 points, with all problems offering partial marks in the form of subtasks.
  • Rated for opening the contest. Unlike with other contests which require making a submission for the contest to be rated, opening the contest and being able to read the problems will cause the contest to be rated.
  • Scoreboard will be hidden.
  • 50 submission limit per problem.
  • Ties will be broken by the sum of the last submission times that increased your score. The first submission times of your highest scores will be used.
  • The contest will follow the standard convention of having all lines terminate in a \n character, with no trailing whitespace.

Furthermore, users are forbidden from using multiple accounts or collaborating during the entire contest duration. Any suspicious behaviour during the contest window may result in a severe penalty including, but not limited to, being placed at the bottom of the scoreboard. Such behaviour includes, but is not limited to:

  • Registering for the contest with at least two accounts.
  • Participating in the contest with an account that is not your primary account.
  • During the contest window, talking about the contest in more detail than answering a yes/no question about whether one participated in the contest. This includes, but is not limited to, posting spoilers about the contest and public speculation of the contest.
  • Attempting to exploit bugs in the platform to subvert the constraints of the contest.

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

You will have 3 hours to complete the contest. After the contest window begins (February 13th, 12:00 AM EST), you may begin at any time. Once you enter the contest, 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 (February 15th, 23:59 EST), whichever comes first.

After joining the contest, you can proceed to the Problems tab to begin.

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

  • It is not guaranteed that the problems will be in order of increasing difficulty. Reading all of the statements is recommended.
  • 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.
  • Python users are recommended to use PyPy 2/3 over Python 2/3 when submitting.
  • It is guaranteed that all the problems will be solvable with C++. All problems have a time limit of at least 2x the reference solution, which is written in C++ and uses this template for I/O. If you're unable to see the template, you must solve this problem. Problems that have been tested in multiple languages may have language specific time limits.

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.


  • 0
    Kirito  commented on Feb. 26, 2021, 7:14 p.m. edit 2

    Ratings for Riolku's Mock CCC have been finalized. If you wish to dispute your rating, please email us at contact -at- dmoj -dot- ca, or message us on the DMOJ Discord.

  • 2
    Badmode  commented on Feb. 16, 2021, 6:49 p.m. edited

    How come no one is rated yet for the contest?

    EDIT: Thanks DMOJ!

    • 5
      Plasmatic  commented on Feb. 16, 2021, 7:37 p.m.

      Be patient, checking for cheaters takes time.

  • -22
    Narcariel  commented on Feb. 12, 2021, 2:27 a.m.

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

    • 9
      31501357  commented on Feb. 15, 2021, 8:25 p.m.

      Imagine not being already banned from the dmoj discord.

  • 11
    Plasmatic  commented on Feb. 10, 2021, 6:04 p.m.


  • -6
    dxke02  commented on Feb. 10, 2021, 4:27 p.m.

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

    • 11
      krish338  commented on Feb. 13, 2021, 11:43 p.m.

      its simulating ccc (theres no live leaderboard in ccc)

  • 16
    noYou  commented on Feb. 10, 2021, 4:11 p.m.


  • 25
    Encodeous  commented on Feb. 10, 2021, 4:07 p.m.

    Good Luck!

    • 13
      Badmode  commented on Feb. 10, 2021, 4:13 p.m.

      You too!

      • 3
        andy_zhu23  commented on Feb. 11, 2021, 5:09 a.m.

        You too!