Welcome to the fifth Don Mills Open Programming Competition of the 2017-2018 season!

The problem writers this time are george_chen, Kirito and r3mark.

If this is your first time participating in the DMOPC, you can learn about our system here.

The contest will use a pretest/systest format for problems 4-6. When you submit to these problems, you will only be judged on some of the test data, called pretests. After the contest, all submissions will be rejudged on the full test data. Pretests typically contain weak test data and do not necessarily include maximum or corner cases.

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

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

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

Some problems offer partial marks in the form of subtasks. If you cannot solve a problem fully, we encourage you to go for these partial marks.

You will have 3 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 3 hours from when you started, or until the hard deadline (noon EDT of Mar. 14th), whichever comes first.

Additionally, this contest will feature a ~7~-th problem (Problem ~0~) for students who are just getting started with programming.

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.
• 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.
• 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.