Dear friends, you might have noticed that the VK logo has disappeared from the Codeforces pages and all of a sudden the place got sort of empty and a little bit gloomy. By the way, it happened not because the VK company lost the interest towards Codeforces and programming contests. Not at all. On the countrary, we have great plans to carry out together! We are infinitely grateful to the VK company for the 4 years of help and support.

We are glad to inform you that now a wonderful company called Telegram is going to help Codeforces. The company is founded by Pavel Durov and it united many brilliant developers with a rich olympic past. It is pleasant and important for us to see Codeforces helped by the people who understand programming contests, love them and value the skills of the community members. The Codeforces team is happy to get the opportunity to continue working and promises to continue dazzling you with contests, innovations and improvements.

Mike Mirzayanov and the Codeforces team

Hello everybody!

I just want to invite you to participate in Codeforces Round #261 (Div.2 only), which will be held on August 15th, 19:30MSK.

This round is prepared by ShayanH, Haghani and me. Special thanks to mruxim for helping us to prepare the problems. Actually, this is our first round and we hope you'll enjoy the contest.

Traditionally, we thank Gerald for helping us to get the contest prepared and also MikeMirzayanov, for the great Polygon system.

Main characters of our stories are two interesting persons, named "Pashmak" and "Parmida"; such a lovely couple! <3

Score distribution will be announced soon.

Have fun. ;)

UPD1: Dynamic scoring system will be used.

UPD2: We recommend you to read all problems, although they're sorted by their estimated difficulty.

UDP3: We also thank Aksenov239 who helped us a lot in fixing the Russian statements.

UDP4: It's over!

Congratulations to all people who solved the five problems.

These are the 7 top official contestants:

1. vanhanh.pham

2. ElemeNtLz

3. MLboy

4. mssjtxwd

5. yyfkiller3

6. phidang

7. roben_76

Editorial will be published soon.

UDP5: We're sorry for the delay. We put a brief editorial here.

Hello everyone!

The second round of MemSQL Start[c]UP 2.0 will take place today, August, 10th, 10:00am PDT. There will be two contests running simultaneously, one for people who participate onsite, and one for everybody else who advanced to the round two. Both rounds share the problemset and are rated based on the combined scoreboard.

Onsite participants will have special prizes for first three places. All onsite participants as well as the top 100 in the online contest will receive a start[c]up t-shirt.

People who have not advanced to the round two can participate in the round unofficially. Unofficial participation will be rated.

The contest will be 3 hours long, and will feature 6 problems. The score distribution is 1000-1000-1500-2000-2500-3000.

Good luck and happy coding!

UPDATE: final results will be delayed.

Hi everyone!

We invite you to participate in Codeforces Round #260(Div. 1 and Div. 2), wich will take place on August 8th, 19:30MSK.

The round was prepared by me, netman and randrew. It's our first round and we hope that tasks will be intresting for you). Special thanks to Gerald, CherryTree, vlad107 and dimad for helping to prepare the round. Also MikeMirzayanov for creating such a good platform.

Good luck everyone!

UPD. In Div. 2 and Div. 1, scores for each problem will be 500-1000-1500-2000-2500.

UPD. We are sorry for the large queue in the end of round.

UPD. Congratulations to the winners.

Div. 1

1. tourist

2. cgy4ever

3. LayCurse

4. ecnerwala

5. snuke

Div. 2

1. allthecode

2. gotowork

3. SMAKH

4. saikrishna17394

5. PashaChemerys

Editorial.

Greeting!

Codeforces Round #259 (Div. 1 and Div. 2) will take place on August 1st, 19:30 MSK.

Setters are: sevenkplus, xlk and me.

Testers are: vfleaking, GuyUpLion, ztxz16 , CMHJT and Trinitrophenol.

Many thanks to Gerald for his help in giving advise about the problems. And we gratefully acknowledge MikeMirzayanov and his team, who bring us the world best competitive programming platform!

Tonight, you will come to Equestria and help our Friendship Princess — Twilight Sparkle to solve those intractable challenges one after another.

Twilight Sparkle is a main protagonist of the series — My Little Pony: Friendship Is Magic.

She is a female unicorn pony who transforms into an alicorn and becomes a princess in the third season of the series. She has a cutie mark of a 6-pointed magenta star with a white one behind it and 5 more smaller ones at each end of the magneta star.

Of course, I guarantee not knowing the storyline and setting won't hold you back from solving these problems~

UPD

In Div. 1, scores for each problem will be 500-1000-1500-2500-2500.

In Div. 2, scores for each problem will be 500-1000-1500-2000-2500.

UPD

Contest is over! Congratulations to the winners! Here are the top 6 in Div.1 division:

1. Petr

2. msg555

3. cgy4ever

4. dzy493941464

5. kcm1700

6. Jacob

And here are the top 6 in Div.2 division:

1. laomao

2. AcySbl

3. mpp121

4. nuip

5. chenzeyu97

6. Horia

Editorial is here.

Hi! In this post I would like to introduce you to an application called Hightail.

Hightail is an automatic tester for programming contests such as CodeForces rounds. It will parse the problem statement, extract sample test cases (inputs and outputs) from it, and verify the correctness of your program against them. It is built to provide maximum automation and to relieve the contestant as much as possible.

A list of Hightail's features:

• parsing problem statements
• parsing entire contests (autoloading all problems)
• scheduling contest parsing ahead of time
• ability to comfortably view, edit and add test cases
• handling of all verdicts: WA, TLE, RE, even AC
• customizable time limits
• ability to create in/out files in your working directory
• detection of floating point values (comparing 0.1 vs. 0.10 does not give WA)
• easy-to-use UI, keyboard shortcuts
• resilient: it is multi-threaded so it will not let your program hang it; it will withstand large amounts of output from your program
• support for all contest languages (C++, Java, Python, ...)
• written in Java and should run on any OS

Some screenshots to give you an idea:

You will find more information on its homepage (scroll down to see the readme). And here's a direct link to downloads.

Hightail started out as a simple program that I wrote for myself quite some time ago, then it became a small open source project when some other people contributed code to it. I think that it is now sufficiently developed that it can be released to the public, i.e. announced publicly here, rather than being hidden somewhere on the net, possible to find only if you already know the name. (It's probably long overdue, actually.)

If you see bugs, have feature suggestions etc., please use GitHub to its fullest extent :) And look at the readme — it has a tutorial on how to contribute to Hightail.

I hope it will be useful to you :)

MemSQL is excited to announce Start[c]UP 2.0 – the second annual programming competition hosted by Codeforces with an onsite at MemSQL HQ in San Francisco, California.

Start[c]UP 2.0 consists of two rounds. Round 1 is online and takes place on July 27th at 10:00 AM PST. Round 1 follows regular Codeforces rules and consists of 5 problems. For this round, the complexity of the problems will be comparable to a regular Codeforces round. There are no eligibility restrictions to participate in the round. The round will be 2.5 hours long, and will be rated.

Round 2 takes place on August 10th at 10:00 AM PST, consists of 6 problems, and uses regular Codeforces rules. The complexity of the problems is higher than a regular Codeforces round, the round will be 3 hours long, and will be rated. Only people who finished in the top 500 in Round 1 can participate. The top 100 in round 2 will receive a Start[c]UP 2.0 T-shirt.

For Silicon Valley residents, MemSQL will be hosting up to 25 people on-site during the second round. The winner of the on-site round will be awarded a special prize.

UPDATE: first round will feature 6 problems, not five as it was announced earlier.

Hello everyone!

Codeforces Round #258 (Div. 2) will take place on July 24, 19:30 MSK. Traditionally, Div. 1 users can take part out of the competition.

The round was prepared by PraveenDhinwa and me (JuanMata). This is our second Codeforces round, and hopefully not our last.

We have tried our best to make the problem statements as clear and interesting as possible. We hope that everyone will enjoy the round. :)

Special thanks to MikeMirzayanov for creating the wonderful Polygon and Codeforces platforms, Gerald for his extensive help in problem verification and testing, and Delinur for translation of problem statements into Russian. Without their help the contest would never have seen the day.

We wish all the participants good luck and high rating. :)

UPD: It is decided to use the dynamic scoring system.

UPD: Contest is finished. You can find the editorial here. :)

UPD: Congratulations to the winners. Here are the top 8 (the only ones to solve all the problems):

1. skank
2. western_theory
3. jurbhm538
4. chenrui9551
5. zhouhebin
6. MaxKU
7. jmas2711
8. hzwer

UPD: Wonderful statistics by DmitriyH can be found here. :)

Hello everyone! Codeforces Round #257 is coming soon.

In this round, you are going to meet our friend Jzzhu. Though my id is jzzhu, the real Jzzhu isn't me, and he is a very cute boy. Now he is facing some challenges. Can you help him to solve the problems?

The problem setters are gagaga5-gagaga and me, and thank ydc, jzc, fanhqme for testing.

Many thanks to Gerald for helping to prepare the round. Also I'd like to thank MikeMirzayanov for creating such a good platform.

Have a good time with Jzzhu!

UPD

In Div. 1, scores for each problem will be 500-1000-1500-2000-2500.

In Div. 2, scores for each problem will be 500-1000-1500-2000-2500.

UPD

The contest is over. Thanks for participating.

Congrats the winners.

Division 1:

1.semiexp

2.kutengine

3.rowdark

4.YuukaKazami

5.mruxim

Division 2:

1.swenyoo

2.chm517

3.Shinka

4.TBH

5.silly_girl

You can find editorial here.

Hello, CodeForces community! I'm happy to tell you about upcoming 256-th round, which will be held for the participants from second division. Participants from first division can take part out of the competition.

I hope, for all this anniversary round. For me it is the first round in which I am the author, in this I will be glad to see everyone. Want to say thanks Gerald for help with preparing contest, Delinur for translating, and of course MikeMirzayanov for CodeForces project.

I am from Krasnoyarsk, and the hero of tasks will be our team talisman Bizon-the-Champion. Hope you like to spend time with him :) See you and good luck!

UPD. Few hours before the start. Score distribution will be dynamic (see more information here)

UPD. Round is over! You can find editorial here.