Hello!

You may find the photos from the VK Cup 2012 on http://vk.com/vkcup

Today is the main VK Cup event: VK Cup 2012 Finals! Good luck to all participants. And to those who don't participate — enjoy the interesting competition. VK CEO Pavel Durov announced the upgrade of a prize fund in the greeting speech at the finals' opening! I'm starting to really regret that I am not a participant.

The participants compete for:

• 1st place — $30000
• 2nd place — $20000
• 3rd place — $10000
• 4-5 places — $2000
• 6-10 places — $1000

Good luck! Wish you only positive emotions. Ready! Steady!...

UPD: The contest is over! I believe Alex_KPR will write about the contest and the closing ceremony soon. Thank you for participation and your interest. Here are the complete standings.

Congrats to the winners. The top-3 is:

• sevenkplus (Yuzhou Gu) China
• s-quark (Qinshi Wang) China
• tourist (Gennady Korotkevich) Belarus

UPD: As you have already noticed, the 16th July at 19:00 will start an unofficial online-version of the VK Cup 2012 Finals. Anyone can participate and feel himself as a finalist. Round will be unrated. If you already took part in the Finals or familiar with the problems, please refrain from participation. All problems will appear in the archive and will be available to everyone.

Hi everybody!

The VK Cup 2012 programming championship finals is going to take place very soon. The organizing committee and jury are working around the clock to set up the event that the participants will like.

Let us remind you that the finals will take place from July, 13 to July, 16. We will choose the best 50 participants by the results of VK Cup 2012 Round 3. As soon as we are absolutely sure about who can come to the finals, we will publish the list of the finalists.

We’d like to share some information from the organizing committee headquarters. The finals’ participants will be accommodated in the beautiful Kempinski hotel in the centre of St. Petersburg, on the bank of the Moika. The hotel is located within a walking distance from the Vkontakte office, so there won’t be any exhausting buses and coming across the city’s traffic jams! Please note the roof restaurant with the view on the Palace Square when you take a look at the photos of the hotel.

There is no exact timetable yet, something depends on the time when the participants will arrive and the complexity of the problems (that’s right, the final round may not have the usual timing). The general plan is as follows:

• July, 13: Checking in, having dinner, meeting each other and having fun.
• July, 14: Most of the day will be dedicated to an unofficial entertaining event called Code Game Challenge (special for VK Cup 2012). Also a short testing tour is planned on that day. In the evening the great dinner will be topped with Code Game Challenge Show – watching the strategy tournament on a large screen.
• July, 15: The main day of the competitions (good luck!). In the evening we’ll reward the winners and celebrate all finalists (I am sure that everyone will be pleased :));
• July, 16: Going home.

Vkontakte and Codeforces are very glad to see the students’ interest in VK Cup 2012. Despite us inviting only young coders to the championship (the age limit should not exceed 23 years), nearly 6000 participants registered there. They geographically cover practically all countries of the world! We are very glad to see that almost all coders who advanced to the finals could make it to St. Petersburg. The winners will get worthy awards, and at this point we are happy to announce that the championship prize fund has been increased! You’ve got an aim to fight for and do your best to win!

• 1st place — $20000
• 2nd place — $10000
• 3rd place — $5000
• 4-5th place — $2000;
• 6-10th place — $1000.

Easy journey to the finalists,
The VK Cup 2012 jury and organizing committee.

Questions and Answers

• What will be the rules of the Final Round? The round will be held by the rules of Codeforces, it will be 2 or 2.5 hours long. The dynamic problems' scoring is likely to be used.
• Will we use the PCs that you will give us, or our own PCs? The participants will use special workstations prepared by the VK Cup Team. It is not allowed to use one's own laptops. You may bring a USB-keyboard, but it should not have superior features.
• What operation system will be used? We hope to give the oppotunity to boot Ubuntu 12.04 or Windows at the participant's choice. We are working on it now. We will install a wide list of free software on both OS.
• Is it possible to use a prewritten code? Basically no, it is only allowed to use the code written on the competition. But you may use the code written on the practice session or on the CodeGame coding phase.

Saint-Petersburg photos

Hello everyone!

Today, 8-th of April, the third round of the VK Cup 2012 will take place. It's the last selection round. Let me remind you that the registration for this round is also required and it’s closed five minutes before the start.

It's rated round. It's allowed to participate out of competiotion. For all such participators it's also rated round. If you participate out of competition, you may play in the second division.

The problemset has been developed by various authors from VK, Codeforces and Saratov State University.

We worked hard to make problems more hard than usually but solvable in two hours. We hope, participation in the round will be interesting for you and only best of the best will pass to the Final Round.

This round will be run according to Codeforces rules: with room assignments, hacks and usual score decrease. It will be rated for you either if you participate in VK Cup or just solve it as a normal round.

Top 50 competitors will advance to the Final Round. VK Cup Final will occur in July in Saint-Petersburg.

Please, to make the round even more interesting for you, read the statements of ALL problems.

Good luck and try to win!

UPD1:

In Div. 2 Edition it will be used dynamic problem costs http://mirror.codeforces.com/blog/entry/4172. The problems will be ordered by increasing of expected difficulties, but their max scores will be determined according to the number of participants solved them.

Hello!

Welcome to the VK Cup 2012 Wild-card Round 2!

It will be a week-long contest with the only problem. It seems the problem doesn't have an exact solution. So as better answer your solution finds as more points you'll get! Of course, it is not all the details. Full text of conditions and the rules of scoring you will be able to read immediately after the round starts.

If you was an official VK Cup 2012 Round 2 participant but didn't advance to the Round 3, you have the last chance to do it! Take part in VK Cup 2012 Wild-card Round 2 and be in the top 25 to advance to the Round 3. All others are members of the community can take part in the round out-of-competition, just for fun. Anyway, it will be unrated round to any of you.

Remember that after the contest ends your last attempt which passes at least one test will be judged on the main testset. You may try to solve problem as many times as you want.

Good luck! Let the best man win!

P.S. I must leave it here. During the contest is strictly forbidden to post/discuss algorithms/approaches for the problem, share any conclusions about the problem. You can not share the results (including just report score points) of the solutions on any tests. It is prohibited to publish tools to simplify and automate the process of solving the problem.

Thanks Nickolas, for the great problem!

UPD: The contest is over, the testing is completed. Congratulations to the first 25 finishers — standings, you are in the VK Cup 2012 Round 3!

Hello everyone!

It’s time for the second round of the VK Cup 2012. Let me remind you that the registration for this round is also required and it’s closed five minutes before the start.

The problemset has been developed by various authors from VK, Codeforces and Saratov State University. We worked hard to make this time interesting for competitors and to have the best ones in the next round.

This round will be run according to Codeforces rules: with room assignments, hacks and usual score decrease. It will be rated for you either if you participate in VK Cup or just solve it as a normal round.

Top 175 competitors will advance to the second round immediately. 25 more competitors will advance to the second round via the second unusual rules wildcard round on March 28. This round will consist of only one problem with inexact solution.

Please, to make the round even more interesting for you, read the statements of ALL problems.

Good luck and try to win!

The contest is over. My sincere respect to the winner in overall run nab who solved all 10 problems in 1h 25m, and congratulations to the winner in the official contest winger who repeated this heroic deed in 1h 52m.

Here is the editorial.

The language of this round is Factor — a stack-based functional language with a sophisticated system of built-in libraries (dictionaries).

Hello everyone!

It's time for the first round of the VK Cup 2012. Let me remind you that the registration for this round is also required and it's closed five minutes before the start.

The problemset has been developed by various authors from VK, Codeforces and Saratov State University. We worked hard to make this time interesting for competitors and to have the best ones in the next round.

This round will be run according to Codeforces rules: with room assignments, hacks and usual score decrease. It will be rated for you either if you participate in VK Cup or just solve it as a normal round.

Top 700 competitors will advance to the second round immediately. 50 more competitors will advance to the second round via the first unusual rules wildcard round on March 18.

There's one wish for everyone from Burunduk1: “Please, to make the round even more interesting for you, read the statements of ALL problems.”

Good luck and try to win!

Update: congratulations to all competitors with 1712 or higher score: you advance to the second round!

Update2: editorial is available: http://mirror.codeforces.com/blog/entry/4097

Update3: Several cheaters have been removed, the results now slightly differ. All participants with 1684 or higher score advance now to Round 2. Everyone else is invited now to the first wildcard round, the last chance to advance.

Hi everybody!

Let me remind you that on the 9th of March, at 08:00 the second qualification round of the VK Cup 2012 championship will start.

It is the last chance to advance to the Round 1. Contestants who gain a score equal to the 800-th place finisher score or greater will advance to the Round 1.

You will find a few simple problems, roughly ordered by the increasing complexity. During the qualification rounds the problems are judged only on pretests and system testing will take place after the end of the qualification round (round continues for 24 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The qualification rounds have no hacks or decreasing values of the problems.

The round will last for 24 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best men make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end. The results of the round will not affect the rating, non-competitive participation in the round is not allowed. However, all tasks will go to the archive after the end of the round.

Best of luck and enjoy solving the problems!

UPD: System testing completed, score to advance to Round 1 is 3500 3450. Congratulations to all advancers!

UPD 2: We've removed cheaters and score to advance decreased to 3450!

Hi everybody!

Let me remind you that on the 3rd of March, at 20:00 the first qualification round of the VK Cup 2012 championship will start.

You need to participate in at least one qualification round to make it to Round 1. Contestants who gain a score equal to the 800-th place finisher score or greater will advance to the Round 1. If you won't participate in the Qualification Round 1 or if you failed to advance to Round 1 by its results, than that's not a problem — you can have a try at the Qualification Round 2 on March, 9.

At each qualification round you will find a few simple problems, roughly ordered by the increasing complexity. During the qualification rounds the problems are judged only on pretests and system testing will take place after the end of the qualification round (round continues for 24 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The qualification rounds have no hacks or decreasing values of the problems.

The round will last for 24 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best men make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end. Yes, we had a false start with registration of the qualification. We haven't switched on the Championship participant registration check function. If someone managed to register to the round on the 2nd of March, please do it again.

The results of the round will not affect the rating, non-competitive participation in the round is not allowed. However, all tasks will go to the archive after the end of the round.

Best of luck and enjoy solving the problems!

UPD: The round is over. 12907 submissions to be judged on system tests!

UPD 2: System testing completed, the final results are available.

Overview

The VK Cup Championship is an open computer programming competition that is held by VK, Codeforces and Saratov State University. VK is the largest European social network with more than a 100 million active users. The Championship Final Round will be held in July in St. Petersburg. Top 50 contestants of the Round 3 will be invited to the Finals, with trip expenses covered by the organizing committee.

Eligibility

You are young and you like to solve programming problems? Then this championship is for you! Anyone meeting the following criteria is eligible to compete in the VK Cup:

• must be at least 14 years and at most 23 complete years of age (by the moment of registration);
• current employees of VK and/or members of organizing committee/jury are ineligible to participate in the VK Cup;
• must be eligible for participation in Codeforces contests.

Thus, the intended audience of the championship are mainly high school and university students. To participate in the championship, you have to register beforehand.

Only individuals are allowed to take part in the Championship. No teams, no joint discussions and etc.