Welcome to the Canada Day '21 Contest!

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

This contest will consist of 6 problems, the difficulty of which may range anywhere from CCC Junior to CCO level.

You will have 2 hours to complete the contest. After the contest window begins, 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 2 hours from when you started, or until the hard deadline (00:00:00 EDT of July 6th), whichever comes first.

After joining the contest, you can proceed to the Problems tab to begin. You can also go to Users if you wish to see the rankings.

Here are some additional parameters of the contest:

• The problems are NOT all of equal weighting. You can check the weighting of the problems when the contest begins.
• Problems will be approximately increasing in difficulty. Reading all of the statements is recommended.
• Checkers: unless otherwise specified, standard.
• It is guaranteed that all the problems will be solvable with C++.

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

• 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.

Clarification requests for the contest must be routed through the clarification system provided on DMOJ, and not through other channels including but not limited to Discord and Slack. Furthermore, all clarification requests will be handled the way they normally are in IOI. Note that, in particular, clarification requests must come in the form of yes/no questions.

Due to rampant issues with cheating on contests that has happened recently, any suspicious behavior during the contest window may result in your rating being impacted negatively. Such behavior 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.

Punishments may include performance being unrated or, for more serious infractions, being forcibly ranked at the bottom of the scoreboard.

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.