By zscoder, 6 weeks ago, In English,

Hi all!

On May 13, 12:35 MSK, Tinkoff Challenge — Final Round will be held. Standings of the official finalists are availiable here.

The authors of the round are me (zscoder, Zi Song Yeoh), AnonymousBunny (Sreejato Kishor Bhattacharya), hloya_ygrt (Yury Shilyaev).

Special thanks to KAN (Nikolay Kalinin) for coordinating the round, winger (Vladislav Isenbaev) and AlexFetisov (Alex Fetisov) for testing the problems. Also, thanks to MikeMirzayanov (Mike Mirzayanov) for the Codeforces and Polygon system.

There are seven problems and the duration is two hours. Scoring will be announced before the round.

Top 20 participants of the Elimination Round will compete in the Tinkoff Office.

The round is rated. Division 1 and Division 2 will have the same problemset with seven problems.

We hope everyone will find interesting problems and get high rating!

UPD : Scoring Distribution : 500 — 1000 — 1750 — 2000 — 2500 — 2750 — 3500

UPD2 : The editorial is out!

UPD3 : Congratulations to the top 10 :

  1. V--o_o--V

  2. LHiC

  3. Um_nik

  4. Petr

  5. Shik

  6. TakanashiRikka

  7. Seter

  8. SirShokoladina

  9. matthew99

  10. DBradac

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By MikeMirzayanov, 6 weeks ago, translation, In English,

Hello, Codeforces!

I'd like to invite you to join in Playrix Codescapes Cup for the both divisions that will be held on May 11 at 18:35 MSK. The round is rated and open for everyone.

Problems are prepared by KAN, Al.Cash, MikeMirzayanov and fcspartakm. Huge thanks to Playrix company for making this round possible. Hope you enjoy the round!

Playrix is one of the leading mobile games development companies in the world. Its distributed team consists of 450 professionals from around the world. The company has released three successful mobile free-to-play games – Township, Fishdom and Gardenscapes. All of the projects have consistently been among the Top 50 Grossing Apps for iOS and Google Play since their release.In 2016, Facebook named Gardenscapes game of the year.

Company is looking for Russian-speaking C++ developers.

Prizes from the Playrix company:

  • Top 1: iPadPro 9,7 + PowerBank + T-shirt with logo
  • Top 2-5: PowerBank + T-shirt with logo
  • Top 6-50: T-shirt with logo
  • (New!) Random 5 participants (not from top-50, submitted at least once): T-shirt with logo

Congratulations to the winners!

  1. tourist
  2. LHiC
  3. subscriber
  4. W4yneb0t
  5. enot110

The problem analysis is published.

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By tourist, 7 weeks ago, translation, In English,

Hi everyone!

The last elimination round of VK Cup 2017, Round 3, will take place on May 7 at 18:35 MSK (check your timezone here), along with separate Codeforces Round #412 for both divisions. All three rounds will be three hours long, and all three rounds will be rated.

The contest "VK Cup 2017 — Round 3" is for teams qualified from Round 2 or Wildcard Round 2. The top 20 teams will advance to the final which will be held in July 2017 in Saint Petersburg!

Huge thanks to KAN, qwerty787788, PavelKunyavskiy, AlexFetisov, MikeMirzayanov, and VK company for making this round possible.

Codeforces will be the main character of most problems. Don't forget that it's useful to read the statements of all the problems.

Good luck!

As we're in year 2017, the scoring will obviously be static. The exact scoring distribution will be announced before the round.

UPD 1. The scoring distribution is:

Div. 1 and VK Cup Round 3: 500 — 1000 — 1750 — 2500 — 2750 — 3500

Div. 2: 500 — 1000 — 1500 — 2000 — 2750 — 3500

UPD 2. Due to yesterday's registration troubles the start of the contest is delayed by 10 minutes.

UPD 3. Congratulations to the winners!

VK Cup Round 3:

  1. zemen, Zlobober
  2. V--o_o--V, LHiC
  3. RomaWhite, witua
  4. YakutovDmitry, BudAlNik
  5. Golovanov399, I_hate_ACM

Div. 1:

  1. Petr
  2. yosupo
  3. rng_58
  4. uwi
  5. Nezzar

Div. 2:

  1. ltaravilse
  2. btk15049
  3. RCG
  4. SUSTechDFS
  5. hieutrungle

UPD 4. Tutorial is now available.

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By Sa1378, history, 7 weeks ago, In English,


I'd like to invite you to join in Codeforces Round #411 that will be held on May 4 at 17:35 MSK.

Actually I didn't do anything for this contest :) and most of the contest is prepared by my good friends ChamrAn and MohammadJA. Also Hifdah, Navick, Folorn, kastarika and I helped them in testing problems, writing statements and these sort of things. At the end, Thanks to KAN for his huge help in all of the contests and MikeMirzayanov for great Codeforces and Polygon platforms. (Sorry if there's someone I didn't mentioned, This is everything I know).

Each division contains 6 problems (4 common problems). Hope you enjoy them.

The round is rated and score distribution will be posted soon and good luck and have fun and hope you high ratings and all the other words that should be told.

UPD 1 Contest delayed by 10 minutes.

UPD 2 Contest delayed by 5 minutes. :)

UPD 3 We can see the scores now in contest page.

UPD 4 Contest is finally over, Hope you enjoyed the problems. Cause of technical issues editorial will be posted tomorrow.

UPD 5 And here are the top5 in each division:













And also congratulation to hahaschool, MKyzy and shanin who solved problem F in div2.

UPD 6 Editorial is ready now.

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By MikeMirzayanov, 7 weeks ago, translation, In English,


Are you missing something new? I have something to please you.

Regularly I host some events — Olympiads, onsites, and eventually, examinations and tests for students. On the one hand, Codeforces already offers a unique functionality — groups, the integration with Polygon, the possibility of choosing tasks from the archive and so on. But it doesn’t enough!

Domains for groups

Here is an example of such group. It is open for all — join it and look:


Now when you are editing a group, you can specify its subdomain (from 3 to 20 alphanumeric characters, starts with a letter). When you specify the domain, the group will be accessible by a link According to this link, the following is correct:

  • Nothing extra will be displayed — the site contains only the information about competitions and blogs of your group and nothing else.
  • All you need to display — is an HTTP access to If you host the official contest, important coaching or examination — block all the rest of the Internet, except for this IP-address.
  • Today such groups can only contain private competitions and trainings. For example, you can make your mashup and set it up as you need. Maybe, later we will make something with this restriction, but for now — it is like this.
Permitted subnets for the domain

To be sure that extra people will not click on your link, you can block the access to it by IP. Specify the exact IP or subnet address. For example,;

The language of the interface of the domain

Probably, when you host the event, only the English (or only Russian) interface is enough for the participant. Use this setting to select the desired behavior.

Header html

You can change the site header at, so that there will be not the familiar logo of Codeforces, but the logo or name of your event. For example, when I host the inter-university Olympiad in Saratov, I set it to <h3>Interuniversity Olympiad on programming 2017 (Saratov)</h3>.

Users of the domain (sidebar)

It is very likely that if you hold an Olympiad or something similar, participants may not have the Codeforces account, the information about participants comes from a separate registration, and you want to see usual names in the interface, such as ‘John Doe, Berliandsky SU, 3 Course’, rather than the participant’s handle.

You can add synthetic users to your group with a domain (using these accounts, you can only log the group through the domain). Use the special function “Users of the domain”. Each line corresponds to one user and must be written in the format: contest ids (separated by commas) | Handle | Password | Name. Here's an example of this setting for the domain

213380 | u01 | 371111 | Petr Korotkevich
213380 | u02 | 627492 | Gennady Soejima
213380 | u03 | 491591 | Makoto Knuth
213380 | u04 | 581711 | Donald Cormen
213380 | u05 | 057259 | Thomas Mitrichev

Yes, you can feel like Peter Korotkevich, log on, and use the login u01 and the password 371111.

Privacy settings

You have a possibility to set all as you wish. For example, to maximally block the access to the group (only by the domain, do not allow extra users), make the closed’ group, and the policy of registering of its membersonly by invitation`. In this case, only domain users (see the point above) and users invited to the group will be able to access the domain address.

For private contests you can set additional settings:

  • Allow practice — whether it is possible to solve problems after the official termination in an informal mode of upsolving.
  • Allow virtual participation — whether it is possible to participate virtually after the official termination (or whenever you want, if there is no start time).
  • Allow out of competition participation — it is reserved for out of competition participation, while only the users of the domain can be registered as out of competition (for the right users, add the symbol 'o' after the contest id, for example “213380o | u01 | 371111 | Petr Korotkevich”).
  • Allow self-registration — whether it is possible for participant to make a self-registration (if no — register him).
  • Allow unregistered users to observe the competition — whether it is possible for the participant of the group who is not registered to a contest enter the contest and see the problems, status, standings and other details.
  • Turn on common status — whether it is possible for participants to see the information about other participants’ submissions, or the information about their own attempts is the only available.
  • The duration of freezing and unfreeze time. Be careful during transfer of the contest — unfreeze time must be changed independently.
  • The policy for showing tests. Here are possible options: "do not show at all", "show failed tests of own solutions", "show all tests completely".
  • The policy of showing other people's attempts. Here are possible options: "do not show at all", "show to participants who solved the problem," "show to everyone."

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By Egor, history, 7 weeks ago, In English,


World Finals is near us once again and I am trying to collect data about participants once again. This year we are able to collect your Codeforces and TopCoder handles through profiles. If you'd log in into the site and go Profile -> Social Media you'd be able to enter your handles. I would kindly request everyone to do just that.

I'll publish data I gathered in a couple of days, if you notice any errors I'd appreciate if you post about them either in comments to this post or in personal messages

UPD: Preliminary data

Last update: 22.05 10:45 MT

Data will no longer be pulled from Baylor database, if you want to update something — fire me personal message

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By Zlobober, 2 months ago, translation, In English,


Midnight tonight (UTC +3) starts the Yandex.Algorithm 2017 Qualification Round. Round lasts for two days in a virtual mode. The contest itself is 100 minutes long. You may start your participation in any moment of time between 21:00 UTC of Friday and 20:59 UTC of Sunday, inclusive.

In order to participate in a competition, you have to complete your registration. It will remain open for everybody until the end of the qualification round.

Those who already successfully submitted at least one problem in a warm-up round are already qualified to the elimination round of the competition. For everybody else in order to be qualified it is necessary to successfully submit at least one problem in a qualification round.

The link to the contest will appear on the site of a competition shortly before the round start time.

Enter the contest!

Let us remind you that discussion of problem statements and solutions is prohibited until 22:40 UTC of Sunday (the latest possible contest end time for a participant). After that you may discuss problems and solutions in comments of this post or the editorial that will appear after the end of competition.

Good luck!

UPD: There is about 6 hours left to register and participate. Don't miss!

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By RussianCodeCup, history, 2 months ago, translation, In English,

Hi, everyone!

There are already more than 400 participants who are preparing for the Elimination Round of Russian Code Cup 2017. If you are still among those who has not qualified yet, we invite you to take part in the Third Qualification Round that will take part this Saturday, April 29, at 14-00 Moscow Time. Top 200 participants will also qualify to the Elimination Round and will be able to compete to get to the Final Round of Russian Code Cup 2017.

Good luck and see you at!

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