Hello everyone!

Once again we invite you to participate in the 24-hour team programming contest Asseco Programming Marathon24 Gdynia 2014. Powered by CodiLime. The first edition in 2013 was quite a success: 243 teams of three from over 20 different countries were registered for the contest and 30 teams from 8 countries were qualified for the finals in Gdynia.

In the contest teams of three can participate. There is no limit concerning the age or education of contestants. Also there is no limit in equipment, programming languages or materials you can use during the contest.

The contest consists of two stages. You can check out problems from the first edition to familiarize yourself with the format. This year's tasks will also be prepared (among others) by Tomasz Idziaszek monsoon and Wojtek Nadara Swistakk.

The first stage are qualifications, which will start on 11th October 2014 at 9:00 CEST and will last for 5 hours. There will be 5 algorithmic problems, to which 10 test cases will be provided. You only submit outputs to the tests and you get immediate feedback on your score.

No more than 30 teams with the highest scores will qualify for finals. They will take place in Pomeranian Science and Technology Park in the city of Gdynia in Poland. Finals will begin on 29th November 2014 and will last for 24 hours. There will be 3 problems, which will require you to write a program communicating with the contest server through the TCP/IP protocol.

For three teams with the highest scores in finals there are prizes amounting to over 30 000 PLN in cash. For more information visit our site: marathon24.com. The registration closes on 9th October 2014.

Update: Also be sure to take part in Codeforces Round #270, for the top 25 participants of this round will get Marathon24 T-shirts!

Good luck and have fun!

Recently we ran another ACM ICPC quarterfinal qualification contest, whose results influenced the list of teams that will go to Saratov this autumn. The corresponding gym contest on Codeforces will be held on Sunday, Sep 21, 2014, at 11:00 AM.

Link to the contest: 2014, Samara SAU ACM ICPC Quarterfinal Qualification Contest

The list of our previous contests:

• 2012, V Samara Regional Intercollegiate Programming Contest
• 2012, Samara SAU ACM ICPC Quarterfinal Qualification Contest
• 2013, VI Samara Regional Intercollegiate Programming Contest
• 2013, Samara SAU ACM ICPC Quarterfinal Qualification Contest
• 2014, VII Samara Regional Intercollegiate Programming Contest

Hello everyone! Codeforces Round #268 is coming soon! We invite you to participate in this round. It will be held on September 20th at 17:00 MSK.

Problems have been prepared by me. Thanks xyz111 and dhh1995 for giving me the idea of some problems. Thanks vfleaking, foreseeable, MinakoKojima, Ruchiose and xllend3 for testing.

I also want to thank Gerald for helping to prepare this round, Delinur for translating the statements, and also MikeMirzayanov for Codeforces and Polygon.

It is my first round on Codeforces. Hope you will enjoy this round.

You'll help a boy named Little X in this round. Good luck and have fun :)

UPD

Round has finished. Thanks for participating.

Congratulations to the winners.

Div. 1

1. PavelKunyavskiy
2. Kostroma
3. HellKitsune
4. SirShokoladina
5. DemiGuo

Div. 2

1. manman
2. topcodecheforces
3. mhy12345
4. GS_ZJ_137
5. z.last

Congratulations to ecnerwala, the only participant to solve the problem D!

Unfortunately, no one has solved the problem E in both divisions.

Editorial for the round will be added tomorrow.

UPD

Editorial is here.

Hello, guys!

I invite you to take part in the last year's competition which took place in Kaunas University of Technology and had participants from three different Universities in Lithuania.

The best participant was selected to KTU #1 (the 30th place in the last year's ACM finals) and other top KTU participants were selected to KTU #2 and KTU #3 teams.

Moreover, some of the hardest tasks were used in the preparation for IOI competition.

The contest is scheduled on Saturday, Sep 20, 2014, at 12:00 PM.

As the contest has three stars of complexity, it may be very interesting for Div. 2 participants, but I don't recommend it for Div. 1 participants and those who already participated in the contest.

All kinds of feedback are gladly accepted, as this contest is also a dress rehearsal for this year's KTU qualification round which is prepared with Polygon and will be made public for all Codeforces participants.

Enjoy the contest!

Solutions written by the authors of the problems:

• Problem A
• Problem B
• Problem C
• Problem D
• Problem E
• Problem F
• Problem G
• Problem H
• Problem I
• Problem J

All problems have been fixed

Welcome to 2014-2015 CT S02E02: Codeforces Trainings Season 2 Episode 2 (CTU Open 2011 + misc). The training duration is 4.30 hours. It is opened for teams as well as for individual participants. After the end you may use the practice mode to complete problem solving. Also it will be availible as a virtual contest for whose of you who can't take part today. Please, do not cheat. Only fair play!

It is possible that the problems will be too easy for some participants, it is possible that we will add some problems.

Good luck!

Hi everyone!

Codeforces Round #267 will take place on September 18th at 19:30 MSK My name is Yura and this is my first Codefocres round and I hope not the last.

I'd like to thank Fedor Korobeinikov (Mediocrity) and Alex Vistyazh (netman) for helping me to test all the tasks and prepare this round. Also, special thanks Gerald for helping me to prepare the tasks, Delinur for translation of all problem statements into English and MikeMirzayanov for Codefocres and Polygon.

I hope that everyone will find the problem for himself, and plunge into the student's life.

Good luck! =)

470A - Crystal Ball Sequence

As usual, the first problem tests competitors' ability to do basic math, and in this case it is even easier than the sample — without any loops.

^'0-
$ 1+*3*1+.

470B - Hexakosioihexekontahexaphobia

This problem uses more advanced language concepts — loop, conditional execution and even named variables! Variables are convenient to use as loop counters and result accumulators, so as to avoid stack manipulations for the same purpose.

The contest is over. 13 people solved all problems — you guys are amazing!

The editorial will be available here.

Today's language is FALSE, stack-based esoteric programming language invented over 20 years ago.

The traditional A+B problem (integers A and B are separated with a space) can be solved like this.

To test your solutions, you can:

• download source code in C of the original interpreter here. Testing system uses this interpreter with -q option.
• use "Custom Invocation".
• use online interpreters (they differ from the reference interpreter a bit but make debugging much easier): 1, 2.

Useful links:

• language description by its author Wouter van Oortmerssen
• Progopedia article
• examples at Rosetta Code

Notes:

1. Language description contains instructions ø and ß. The reference interpreter uses O and B instead (both online interpreters support ø and ß).
2. End of file is encoded as #-1, end of line — as #13#10.
3. The stack MUST be empty when program completes, otherwise the interpreter will post an error to stdout, and output will be judged as incorrect.

Surprise Language Round #7 will take place on September 13th, the Programmers' Day.

The rules of the contest are as follows:

• The contest is unrated for everybody.
• The round uses ACM ICPC rules: the standing is defined by the number of solved problems, ties are resolved based on penalty time. Initially the penalty is 0, and for each solved problem it is increased by submission time (since the start of the contest) + 20 minutes for each failed submission. The solution is considered to be correct if it passes all tests from a predefined test set; you know whether the solution is right immediately after sending it. There are no hacks.
• The round has 8 problems, sorted by estimated complexity, and you have 2 hours to solve it.
• Solutions are accepted only in one language, which will be announced at the beginning of the contest. The language was created a while ago, we didn't invent it for this occasion.
• Please reread this post at the beginning of the contest: we will announce the language and add instructions to install the compiler (the contest interface will provide an option to run your solutions online as well) and links to useful manuals. Other than that, learning the language is up to the competitor. You can use any resources to solve the problems (as long as you remember that this is an individual competition); you don't have to limit yourself to the manuals provided in the post.

I hope that the language I chose will be unknown to most of the competitors.

Hi Codeforces!

We would like to invite you to participate in Codeforces Round #266 Div2, which will be held this Friday, September 12th at 19:30 MSK. As usual, Div1 participants can take part out of the competition.

Problems have been prepared by Antoniuk and me. It's the second round prepared by us, and we still hope it won't be the last.

We want to thank Gerald for helping to prepare this round, Delinur for translating the statements, and also MikeMirzayanov for Codeforces and Polygon.

It will be used a standart scoring: 500-1000-1500-2000-2500.

Gl & hf!

UPD. Round has finished. Thanks for participating.
UPD2 Congratulations to top-5 participants:

1) dominator_hza
2) Final_Battle
3) free_pascal
4) vanhanh.pham
5) NUOUN

UPD3. Editorial .