Hello everyone!

Codeforces Round #182 will take place on Sunday, May 5th at 19:30 MSK. This is my sixth Codeforces round and I hope not the last.

I'd like to thank Gerald and sdya for helping me to prepare the round. Special thanks to Delinur for translation of all problem statements into English.

I strongly recommend you to read ALL the problems.

Gl & hf ! :)

Because of technical issue the start of the contest was unsuccessful. Sorry about it. The contest will be UNRATED.

Tutorial.

As you probably know there are International Workers' Day holidays in Russia in the beginning of May. Am I the only person who see a contradiction here? Workers and continuous holydays!

So I decided that the best way to spend May, 2nd is to do something useful. So meet new languages on Codeforces:

• Python 3 (3.3.1)
• MS C# .NET 4
• Go (1.1 RC1)

Also I made an attempt to setup Clojure, but his AOT nature makes any solution (even A+B) to run for at least 1 second :( I believe it is possible to precompile Clojure solution into bytecode, but I haven't found the way yet. Maybe someone can help me?

There are three days before round. Three days to test new languages. Please write comments in case of any issues.

P.S. As extra bonus — I've updated Python 2 to 2.7.4.

On April 6th, III (XIV) Volga Region Open Team Student Programming Contest was held in Samara State University. And now, we invite everyone who haven't already participated in the championship to join the Codeforces training contest version on April 28th (11:00 — 16:00 MSK, UTC+4). We believe that participants of any level will find problems that will be interesting for them. The contest will probably be mostly interesting to participants with violet and orange levels (difficulty is 4 stars).

This contest uses ACM ICPC rules. Use text files input.txt and output.txt instead of stdin/stdout.

Please, do not use the Internet, prewritten code and other sources: participants of the championship could not use any of these.

Contest was prepared by Dmitry Matov (Nerevar), Constantine Drozdov (I_love_natalia), Andrey Gaidel (Shlakoblock), Elena Rogacheva (elena), Sergei Shteiner (steiner), Dmitry Novikov, Alexander Efimov, Gennady Gutman.

Hello everyone.

We invite you to take part in the training on problems of VI Samara Regional Intercollegiate Programming Contest. It was held March 31 in Samara State Aerospace University.

Problem writers are members of team Samara SAU Teddy Bears. Problem tester is ashmelev.

Difficulty is the same as in our previous contests: 3 stars. Duration — 5 hours.

Contest starts this Saturday (April 27) at 02:00 PM (MSK).

Hello!

A few hours later, 25 апреля в 19:30 MSK, you are lucky to participate in Codeforces Round #181 for Div. 2 participants. Traditionally, Div. 1 participants can take part out of the competition.

Problems have been prepared by: Gridnev Vitaliy (gridnevvvit), Ignatyev Alexander (aiMR). We want to thank Gerald Agapov(Gerald) for help in preparation of this round, Michael Mirzayanov(MikeMirzayanov) for marvelous Codeforces and Polygon systems, Mary Belova(Delinur) for translating the problems.

About authors: me and Alexander are third year students of Mathematics Department, Saratov State University. It’s our first round and I hope not last.

We hope you will like these problems, and that it will be fun to solve them.

Also we strongly recommend you to read all the problems.

We wish everyone good luck and high rating!

UPD: Scoring will be dynamic. Problems are sorted by increasing order of difficulty.

UPD1: Editorial here

UPD2: Contest finished. Congratulations to winners:

1. ballmaids02
2. VIProgrammer
3. emachaidze

Hi everyone!

ABBYY’s first programming problem contest is over. Many thanks to all the participants! The winners will be announced in two weeks time. As of now, there are some statistics:

As you can see, this contest has been a pilot one and mostly an experiment. Again, many thanks to all who joined in! We are very happy and proud to receive so many problems from you!

Hello everyone!

Round 2 of All-Russian Programming Championship CROC-2013 will take place today. Round was prepared by sdya, Seyaua, Gerald and traditionally, problem statements were translated to English by Delinur.

Good news for people, who didn't qualify to this round — today everyone can participate out the competition. Additionally, round will be rated for both official participants and out of competition participants.

Remind some facts about the official participants:

• All the participants should be 18+ years old
• The championship finals are going to take place on May, 16-17 in Moscow in the CROC office (50 participants)
• The CROC company pays for the accomodation in Moscow during the finals
• For Russian citizens: the travel expenses around Russia will be covered, the transport expenses outside Russia can be covered possibly partially but you need to contact CROC and clarify it for each particular case
• All finalists should confirm invitation and their participation in finals until May 2

A little bonus: top 200 official Championship contestants will receive t-shirts!

Enjoy problems and good luck!

UPD: Point values for problems will be unusual today. 500-1500-1500-2000-2500 for first division and 500-1000-1500-2500-2500 for second.

UPD2: We are really sorry for technical problems. After some discussion we have decided that this round should be rated. The list of the finalists will be based on today's results.

Hi all!

CodeForces 180 will take place at 19/4 17:30 (CEST). I (SteamTurbine), and Ivan Li (AEtheReal) are the authors of the round.

This time you will need to help some polar bears to solve their problems. You know, life in the arctic is hard, they may face difficulties about catching fish, keeping warm etc.

Thanks Gerald for helping us to prepare the round, MikeMirzayanov for the great platform and Delinur for translation.

We hope that the polar bears are not going to eat you. Good Luck.

UPD: Scoring will be dynamic. Problems are sorted by increasing order of difficulty.

Editorial is here(All except Div 1 E) and here(Div 1 E).

Result (div1):

1. tourist (Solved all!)
2. wjmsbmr
3. tckwok0
4. msg555
5. Erop

Result (div2):

1. Parsa.pordel
2. a88027180
3. Raoul

Some fun facts:

In 297E - Mystic Carvings (written by AEtheReal), the figure in the problem looks like the facial expression "XD" and "囧", which is done intentionally.

Moreover, three lines can intersect in the following 5 ways:

While discussing the problem, we refer those as "川", "囧", "XD", "卄" and "△". Chinese characters are interesting :)

Good day)

Soon is coming Round 1 of the All-Russian Programming Championship CROC-2013. Contestants who gain a score equal to the 400-th place finisher score or greater will advance to the Round 2 (also you need to gain positive score).

Round will be held by usual Codeforces rules (with hacks and decreasing values of the problems). During the round the problems are judged only on pretests and system testing will take place after the end of the contest. The pretests do not cover all possible cases of input data, test your programs carefully.

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, solutions and so on.

The problems were prepared by the group of authors: Pavel Kholkin (HolkinPV), Gerald Agapov (Gerald) and Michael Mirzayanov (MikeMirzayanov). I will add that our team have already prepared for you qualification round and answered the questions during the whole competition. Traditionally thanks to Mary Belova (Delinur) for translating the problems.

UPD1: The problems are sorted by increasing of estimated difficulty. The score dustribution is decided to be not standard a little bit : 1000, 1000, 1500, 2000, 2500.

UPD2: due to the large number of participants, it is decided that it will not be able to participate out the competition. For official contest participants the round will be rated.

We wish all the participants good luck and successful advance to the next round of competition.

Hi everybody!

Let me remind you that on the 12th of April, at 20:00 the Qualification Round of the All-Russian Programming Championship CROC-2013 will start.

You need to participate in the Qualification Round to make it to Round 1. Contestants who gain a score equal to the 2000-th place finisher score or greater will advance to the Round 1 (also you need to gain positive score).

At the Qualification Round you will find a few problems, roughly ordered by the increasing complexity. During the Qualification Round the problems are judged only on pretests and system testing will take place after the end of the Qualification Round (round continues for 48 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The Qualification Round has no hacks or decreasing values of the problems.

The round will last for 48 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!

P.S. You can't take part here unofficially. You may register to the Championship here. The working language of the Championship is Russian, but all the problems will be in English too.

Most agile participants have registered before we implemented validation rules around Championship registration. So some registrations will be canceled. Sorry for it — you may register to the Champ and register for round after it.

UPD: Testing is completed. Unofficially qualification cut-off is 950. Participants with at least 950 points advance to Round 1. It can be changed because of cheaters disqualifications.