Hi, everyone!

Regular Codeforces round #273 for participants from the second division will take place on 16 October, 19:30 MSK. Participants from the first division are able to participate out of the contest.

Problem setter: pkhaustov (Khaustov Pavel, Russia, Tomsk, Tomsk Polytechnic University)

Special thanks to Codeforces team and, in particular, Maxim Akhmedov (Zlobober) for help in round preparations and Maria Belova (Delinur) for translations.

Participants will be given five problems and two hours to solve this problems.

Points distribution: 500-1000-1500-2000-2500

UPD: +10 minutes to start

Good luck!

Hello, everyone! Codeforces Round #272 will be held at this local time. We're looking forward to your participation!

The problems are from dreamoon_love_AA and drazil(that's me) from Taiwan, and thanks 9mmlitswe for some discussion. Also we want to thank Zlobober and Gerald for helping us prepare the round, Delinur for translating the statement into Russian, and MikeMirzayanov for Codeforces and Polygon.

This is our first round on Codeforces, we hope you'll find it interesting! Please read all problem statements and discover what the main character dreamoon_love_AA do in those problems for he's really cute =)

Update1 Note this round will be held 1.5hrs earlier than usual Codeforces rounds, so please double check the starting time in your local time.

Update2 Score distribution!
Div2: 500-1500-1500-2000-2500
Div1: 500-1000-1500-2000-3000

Update3 The contests are over. Congratulations to the winners!

Div1:
1. Petr
2. qwer1561
3. kutengine
4. ifsmirnov
5. TankEngineer

Div2:
1. ridowan007
2. a00012025
3. xavier13540
4. v_Enhance
5. pkq2006

And standings are here:
Div1: результаты
Div2: результаты

Update4 Editorial can be found here. It's finished by now but it's welcome to tell me if anything can be improved!

Welcome to 2014-2015 CT S02E05: Codeforces Trainings Season 2 Episode 5 - 2009-2010 ACM-ICPC, NEERC, Southern Subregional Contest. 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!

In a few hours, Bayan Qualification round begins.

Qualification round will be held as our first official and required round of Bayan Programming Contest 2014-2015. It will begin on October 9th, 06:00 (UTC) for a 72-hour period, and solving only one problem is enough to advance you to the elimination round. This round is going to be an easy event with 3 very easy problems and 5 random participants will be receiving t-shirts.

Whether you are testing your luck for a random tshirt or are aiming for one of 100 tshirts of elimination round, or even if you are already planning for your trip to Tehran, you should not miss the qualification round. (contest.bayan.ir)

Please do make sure that you have fully read the main contest announcement. Lots of your questions has been already answered there.

We would like to thank MikeMirzayanov and his team specially Maxim Akhmedov (Zlobober) once again for all their efforts before and during the warm up round. Polygon was also handy and helpful for problem setting and team collaboration.

To join the stream you can follow contest's updates @bayan and you can follow the images on our Instagram page.

Hello, Codeforces! On 6th October at 19:30 MSK the Codeforces Round 271 (Div. 2) will take place. Div1 participants can take part out of competition, as usual.

I am Ciprian Olariu (scipianus) from Romania and this is my first round on Codeforces. It is more special as it is held right after I became red on Codeforces. I would like to thank Maxim Akhmedov (Zlobober) and Gerald Agapov (Gerald) for helping me to prepare this round, Delinur for translating the statements and also MikeMirzayanov for Codeforces and Polygon platform.

In this round the main characters will be Mole and Marmot, two good friends, and you will help them in their activites.

Please note that this round will have an experimental duration of 2.5 hours and 6 problems. The scoring will be 500-1000-1500-2000-3000-3000.

I hope you will enjoy the round. Good luck and have fun :)

UPD : To avoid overlapping Topcoder SRM #635 and Bayan 2015 Contest Warm Up, we decided to move round to Monday 19:30 MSK

UPD 2 : The editorial was published here

UPD 3 : Round has finished. Thanks for participating. Congratulations to the winners:

stonebuddha

Syloviaely

vanhanh.pham

__PLEASEDONTHACKME__

LOVESY**

• Bayan warm-up round will be held on Sunday, October 5th 2014, 13:00 (UTC) and as indicated before, it will be held on Codeforces. Warm-up round is not a required round but top 50 are going to win t-shirts and it is going to be rated for both divisions.

• Problems have been prepared by mruxim, mR.ilchi, havaliza . We have tried our best to make the problem-set interesting and competitive and we hope you enjoy it.

• It is necessary to have a complete profile on contest.bayan.ir before the warm-up round! And please do make sure you have selected the correct t-shirt size!

• We have upgraded our contest platform, and we've made sure everything is stable, tuned and robust now. Thanks to all those who helped us test the unstable version!

• The unofficial Shortcut! Round is now accessible to all, so you can check the standings and the problems.

• Qualification round which is the first official and required round of Bayan Programming Contest 2014-2015 will begin on October 9th so don’t forget to register right now at contest.bayan.ir if you haven’t already.

• We've created a twitter account to publish Bayan Programming Contest news. Now you can follow us @bayan.

Update 1: The scoring will be: 500 – 1000 – 1500 – 2000 – 2500 – 2500

Update 2: Warm up round is finished now. We have decided to randomly give 5 extra tshirts to 5 contestants ranked between 51 and 550. And as mentioned before, we are going to have 5 random tshirt winners in our Qualification round too.

Update 3: Congratulations to top 50, specially:

1. fotiIe96

2. hogloid

3. sankear

4. flashmt

5. TankEngineer

Update 4: Here are 5 lucky randomly selectes tshirt winners for this round:

1. Dongmin

2. zxqfl

3. shimomire

4. arthur.nascimento

5. SlavaSSU

Update 5: marat.snowbear has published a good editorial for this round.

Welcome to 2014-2015 CT S02E04: Codeforces Trainings Season 2 Episode 4 (US College Rockethon 2014 + COCI 2008-5 + GCJ Finals 2008 C). 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!

Do you want to win a T-shirt? Do you want to learn how to design tasks for programming contest? Do you want to solve 7 tasks in 2.5 hours?

So Codeforces Round #270 is right for you. It was designed by me in California, Assembled in polygon (so Thank you MikeMirzayanov for the system and Gerald for organize and testing), will start on regular time this Sunday, don't miss it!

The organizers of Marathon24 decided to present gifts to the best finishers of the round! Best 25 participants will get Marathon24 tshirts! Thanks!

It is just an image to attract your attention. Real tshirts will be designed specially for Marathon24!

There are some articles introduced how to become a problem setter, like Problemsetter's Memoir and Way of problemsetter, but they focus on the process of contest preparation or high level thoughts. You might still don't know how to begin to write a contest: because you need to come up with ideas about problems in the first place.

In the last 3 years, I've designed lots of tasks, for example, there are 2 Codeforces Round by me (#190 and #228), and there are exactly 100 tasks designed by me on Topcoder. So I want to write a tutorial to share some specific ways to come up with new tasks.. Oh, wait, how about create a contest and write the tutorial in problem statement? So I get this idea: in each problem I will introduce a specific way of design, and I'll tell you how did I use this way to come up with a new task, and you need to solve that new task!

And this round will be a bit special: all contestants from Div1 and Div2 will compete in one contest, and it will contain all 7 problems! The duration is extended from 2 hours to 2.5 hours.

In the last, I'll do some self-introduction like marat.snowbear did in the announcement of last round. I'm Gaoyuan Chen from China, I lived in Beijing for 23 years till this August, and then I went to University of Southern California in Los Angeles to learn Game Design and Game Development. As a game designer, I'll try to make my round interesting and competitive. (And of course, there will be a problem about a popular game!) And I start to use Facebook after moved to US, so if you want to know more about me or want to chat with me, visit my facebook page: https://www.facebook.com/cgy4ever

More information like score distribution (so maybe we will have 3500p for last task!) will be announced later.

Good luck and have fun!

Update1 : score distribution: 500 — 1000 — 1500 — 2000 — 3000 — 3000 — 3500

Update2 : Contest ended. Thanks for participate! Any comment is welcome (you like the task? don't like it? it is too easy? too hard? Do you like the idea of Div1 and Div2 compete together? etc.).

Update3 : Editorial: http://codeforces.net/blog/entry/14028

Update4 : System test finished! Top 5 (in fact Top 6 because of a tie):

1. Petr

2. Egor

3. riadwaw

4. PavelKunyavskiy

5. Jacob and rowdark

Update5 : Thank all of your support! I found I'm on the Top contributors list now. :)

Update6 : Statistics by DmitriyH: http://codeforces.net/blog/entry/14034