geranazavr555's blog

By geranazavr555, 10 months ago, translation, In English

Hello, Codeforces!

I and cannor147, as students of ITMO University, joined the Codeforces team in June. From June to October, we mainly dealt with the development of the Polygon platform. In this post, we would like to present to you a list of what we have done during this time. This list does not include minor bug fixes or any improvements that are invisible to users.

PIN codes for problems and contests

Sometimes very important contests and problems are being developed in Polygon. In such cases, a leader of the jury may be worried about data leaking. For example, it can be so because of the weak password of another member of the jury. PIN code is an additional factor of confirmation the access for the problem or contest and it can be set up only by the owner. It is assumed that the PIN code will be sent in another secure way.

There is a link Create Pin for the owners in the contest interface:

Create Pin in the interface

The form of the PIN code creation

If a contest or a problem has the PIN code, you need to type it before continuing.

The input form for the PIN code

You can manage the PIN code of the problem in the tab Manage Access in the problem interface. The owner can create the PIN code or copy the PIN code from a contest that contains the problem.

Managing of the PIN code for problems

If you use Polygon API, there is a way to send requests for working with problems or contests, that have the PIN code. You have to provide a new additional parameter “pin” in your requests.

Groups of contests

Polygon grows up and the number of contests in Polygon grows up too. Sometimes you want to group some contests. For example, it seems convenient to group contests from the same programming workshop. Now in Polygon you can group some contests for faster management of the access rights for them.

Group of contests

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By geranazavr555, 15 months ago, translation, In English

Hello, Codeforces!

We are glad to invite you to take part in Codeforces Round #568 (Div. 2), which will be held on 19.06.2019 17:45 (Московское время). The round will consist of 7 problems (possibly, plus subproblems). It will be rated for Div. 2 participants.

We, geranazavr555 and cannor147, are students of ITMO University. And we have recently joined the developers team of Codeforces and Polygon. We have prepared this round for more careful acquaintance with the system. We hope that you will enjoy the competition.

Initially, we had prepared the round for Div. 3, but after testing, it became clear that this round is harder than usual such rounds. MikeMirzayanov suggested to make this to be rated for the second division.

Many thanks to MikeMirzayanov for the tremendous work on the creation and development of Codeforces and Polygon and coordinating our work. Also, special thanks to Vshining, PikMike, ZeroAmbition, Vovuh, Lewin, Dave11ar, T-D-K and Azat_Yusupov for testing the round.

Good luck!


The scoring distribution will be: 500 — 1000 — (1000 + 750) — 2000 — 2250 — 2750 — (2750 + 750). The round will last 2 hours and 15 minutes.


Congratulations to the winners:

  1. 2om_neek

  2. m1sch3f

  3. AreEduRoundsEducational

  4. ashutosh450



Editorials are available here.

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