Hello Codeforces!

On May 15, 18:05 MSK will be held Educational Codeforces Round 21.

Series of Educational Rounds continue being held as Harbour.Space university initiative! You can read the details about the cooperation between Harbour.Space and Codeforces in the blog post.

The round will be unrated for all users and will be held on extented ACM ICPC rules. After the end of the contest you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 7 problems and 2 hours 30 minutes to solve them. We hope that everyone will find something interesting in this contest.

The round was prepared by Mikhail awoo Piklyaev, Mikhail MikeMirzayanov Mirzayanov and me.

Here is message from Igor Maksimov, Harbour.Space University.

I want to make an announcement of the upcoming 2nd Hello Barcelona ACM-ICPC Bootcamp that will take place in Barcelona from the 27th of September until the 4th of October 2017, in collaboration with Moscow Workshops ACM ICPC, is an opportunity for teams of different levels to prepare for successful participation in ACM ICPC.

The Bootcamp will be split in two divisions:

• Division A. Designed to prepare students to excel and win medals in the next ACM-ICPC World Finals.
• Division B. Division B. Designed to help teams prepare for the next season of ACM ICPC Regionals and international competitions. This is an appropriate introduction for teams and students new to the world of ACM ICPC and competitive programming competitions in general. The Division B curriculum features thematic lectures and contests.

Harbour.space University introduce the video about the 1st ACM-ICPC Programming Bootcamp held in February, 2017.

Take a part of the upcoming 2nd Hello Barcelona ACM-ICPC Bootcamp that will take place in Barcelona from the 27th of September until the 5th of October 2017.

More information →

Good luck to everyone!

UPD: Editorial is out.

Ready, steady, go!

It's time to find out who the top 50 participants to compete in the Final Round of Russian Code Cup 2017 are. We invite everyone qualified to take part in the Elimination Round this Sunday, May 14, 2017 at 13-00 Moscow Time. Round length is 2 hours. We invite you to russiancodecup.ru, and wish you good luck!

Hello everybody!

Tomorrow, at 10:00 Moscow time will be held Round 1 of Yandex.Algorithm competition, authored by me. I would like to thank Zlobober for all the job he does to make this competition interesting, MikeMirzayanov for the great polygon that ease the preparation process a lot, and everyone, who tested the round and made useful comments. Of course, we did our best to make the problem diverse by topics and difficulty.

See you in the competition dashboard!

UPD Thanks to everyone who participated, hope each of you found at least one interesting problem. We apologize for the situation with problem F, we have googled for all the problems and asked all testers whether they have seen such problems or not, but that didn't helped. The editorial has been published.

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. Syloviaely

7. Seter

8. SirShokoladina

9. matthew99

10. DBradac

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.

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. YakutovDmitriy, budalnik
5. Golovanov399, -imc-

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.

Hi!

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 saliii and MohammadJA. Also amsen, Navick, tundra, 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:

Div1:

1-riadwaw

2-Endagorion

3-al13n

4-molamola.

5-zeliboba

Div2:

1-ConnorZhong

2-_ISB_

3-Dipak

4-hahaschool

5-BlackTools

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

UPD 6 Editorial is ready now.

Hello!

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 a group. It is open for all — join it and look: http://example.contest.codeforces.com

Domain

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 http://yourgroupdomain.contest.codeforces.com. 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 77.234.215.194. 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 http://yourgroupdomain.contest.codeforces.com, you can block the access to it by IP. Specify the exact IP or subnet address. For example, 188.93.56.35;212.193.32.0/19.

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 http://yourgroupdomain.contest.codeforces.com, 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 example.contest.codeforces.com:

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 http://example.contest.codeforces.com, 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 the 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."