By MikeMirzayanov3 days ago, translation, In English,

April 18, 18:00 (UTC) the second Wild-card round of VK Cup 2015 will take place.

Participants are invited to achieve progress in solving an unusual problem. VK Cup teams which were advanced to the Round 2 (and didn't advance to the Round 3) will take part in VK Cup 2015 - Wild Card Round 2 officially. In addition, this round will be open to the public for unofficial participation for everybody. Registration will be open for the whole round duration.

The round will be one week long. After the end latest submission (with positive score) of each participant will be judged on system tests.

Good luck!

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By Zlobober4 days ago, translation, In English,

This Friday, April 17th, 19:00 there will be Round 2 of VK Cup 2015! For all unofficial participants there will be an online mirror that is a usual rated div1-round. Any div1 contestant that does not participate in official Round 2 is able to compete in this mirror.

Round consists of 6 problems that are shuffled randomly. There will be a smooth dynamic scoring system.

Round is brought to you by Codeforces team, VK team and user Errichto, that offered his important help as a part of his donation for "Codeforces 5 years campaign". Significant testing effort was made by user winger.

Good luck and have fun!

UPD: Thanks everybody for participating! Editorial has just appeared. See you on Wild-card Round 2 and mirror of Round 3!

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Announcement of VK Cup 2015 - Round 2
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By PrinceOfPersia9 days ago, In English,


Codeforces round #299 is gonna take place soon(exact time) and I'm the writer. I'm lucky to be the first Iranian author in Codeforces, in your and our new year (2015 and 1394).

Now, I wanna thank: myself(PrinceOfPersia) for writing the problems(:P), MikeMirzayanov for great Codeforces and Polygon platform, Zlobober and DamonSalvatore and sobhan.miryoosefi for helping me prepare this round, Haghani and SoroushE for testing this round, Delinur for translating problem statements into Russian and big thanks to my great buddy, Swift for problem legends and the pictures.

Also, I wanna thank xiaodao for teaching me how to use polygon and testlib and so much other things about it (about a year ago).

This is my first official contest(after all those contests in Gym :D). I hope you enjoy it.

The main character of all problems is Tavas, well-known by eating CoffeeMix without water! Trust me, when he does that it smells awful.

Also, you'll meet his friends.

I hope you enjoy the problems. I wish you all high ratings, many Accepted solutions and Successful hacking attempts. And Hacked instead of Failed System Test.

Scoring will be posted later.

GL & HF ;)

UPD: Scoring will be standard for both divisions (500-1000-1500-2000-2500).

UPD2: Contest is over. We're waiting for system testing. Editorial is published.

UPD3: System test is done. Congratulations to all winners.

Div.1 winners:

  1. jcvb
  2. rng_58
  3. vepifanov
  4. mmaxio
  5. flydutchman

And Div.2 winners are:

  1. l1n4r
  2. 0e352a
  3. grikukan
  4. wilcot
  5. boray

Good job everyone, see you ;)

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By Ne0n259 days ago, translation, In English,

Hello, Codeforces!

I'd like to invite you to Codeforces Round #298 (Div. 2). It will be held on Sunday, April 12 at 19:00 MSK and Div. 1 participants are invited to join out of competition.

Problems have been prepared by Maxim Mescheryakov (Ne0n25) and Danil Sagunov (dans). We hope you'll find them interesting.

Great thanks to Maxim Akhmedov (Zlobober) for helping us preparing the contest, to Maria Belova (Delinur) for translating the statements into English, to Mike Mirzayanov (MikeMirzayanov) for the great Codeforces and Polygon systems and ideas of some problems. Also thanks Vitaliy Aksenov (Aksenov239) for writing solutions.

You will be given six problems and two and the half hours to solve them.

UPD: Scoring system 500-1000-1500-2000-2500-3000

UPD2: Competition completed! Thank you all!

UPD3: Congratulations to the winners!

  1. xuanhien070594

  2. misis

  3. Mikagura_Seisa

  4. plem

  5. 11111111

UPD4: Editorial here

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By MikeMirzayanov9 days ago, translation, In English,

Hello Codeforces.

This is a really good and pleasant day for us. We are happy to announce that the fundraising campaign on Codeforces is successfully completed and its results are even beyond our expectations. Thank you for your support, your trust and your kind words.

By the way, we have some more unprocessed PayPal transfers: for unknown reasons the notifications in some cases didn't contain some data needed to process them automatically. We will process them manually and update the data as soon as possible.

To all of you waiting for our present in the mailbox, please update your Codeforces profile information or make sure that it already is complete and up-to-date.

Mike Mirzayanov

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By MikeMirzayanov12 days ago, translation, In English,


It is only a day before the end of the fundraising campaign dedicated to the 5th anniversary of Codeforces. We are glad and grateful for your help and support. We are working hard to justify your and our own expectations.

For those who are not accustomed to rush, remember that you still have a little time to join the remarkable list of our friends — help us and get a gift from the Codeforces team!

When summing up, of course, we mostly want not to count money, but to assess progress and the work done. I looked at all of our commits to Codeforces and Polygon, and made a digest of changes.

I did not include to the digest improvements in the depths of system's backend (although stability progress should be visible), infrastructure jobs, org. work around the championships — but, believe me, there were many items too.

And here is the list of our achievements for about two months after anniversary.

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By Monyura7 weeks ago, translation, In English,

Hello everybody!

Our company wants to say thanks to Codeforces and congratulate it with the 5 years birthday:)

A year and a half ago I and the team (Sfairat, olpetOdessaONU, Sklyack) met Victor Shaburov and became co-founders of Looksery. We work in Computer Vision and Augmented Reality areas.
On behalf of all our collective I want to say thanks to MikeMirzayanov and Codeforces team, you do a great matter, and I'm sure it will have a huge impact on the IT segment of the nearest future. To tell the truth, I don't know how we would be able to solve the problems that we had at the beginning of Looksery path if there were no Codeforces or ACM ICPC in our lives.
I would like to tell a few words about our organization, clarifying my opinion about popular topic of the last few days about competitive programming and "real" job.
In Looksery, most of the competitive programmers work on the "core" functionality, but you can also find them in each of the Android, iOS and Backend departments.
During the work on the project we've found out that Computer Vision is a field where ability to write optimized code and skills of solving the problems, which haven't ever been solved before, are extremely required.
Those, who have iPhone4S (or higher) or device with Android 4.3+ may take a look at our application by this link
At the end of this fall we've successfully launched iOS app, got 2 000 000 users, become top 1 overall in Mexica and Best App of Year by Vogue :) Recently we have launched Android app.
You could see a short demonstration of our product below. The video was created in our app on iPhone 6+:
We are happy that now in our team are Sfairat, olpetOdessaONU, Sklyack, tiirz, LesyaPhoenix, MrDindows, Rubanenko, Krasnokutskiy, 2222, MaximM, Avalanche, Igor_Kudryashov, Kepnu4, and many others.

We will prepare round on Codeforces on the 6th of June, with prizes and interesting (we will do our best:) ) problems. I invite everybody to take part in it, all the details will be in a separate topic.

Have a good day,
Looksery Inc

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By I_love_Hoang_Yen2 weeks ago, In English,

Today I came across this article, in which "Peter Norvig said that one thing that was surprising to him was that being a winner at programming contests was a negative factor for performing well on the job".

Normally I don't care about these topics, but this is from Google — where they have good population of high rated competitive programmers and the claim is backed with data.

The article mentioned one point: "programming contest winners are used to cranking solutions out fast and that you performed better at the job if you were more reflective and went slowly and made sure things were right". Though I don't think this is true. For example, being competitive programmer taught me:

  1. bugs can be everywhere & we must code carefully
  2. many problems have amazing solutions, and it's not a good idea to start coding anything that comes to mind.

Some comments talked about how competitive programmers write unmaintainable code or appear arrogant. Having lots of friends who are competitive programmers and read lots of comments here, I believe that these are also not the case.

  • Yes, amongst rude comments made on Codeforces, many are from reds, but many are also from yellows, purples, blues, greens... and I think majority of high rated people here are very reasonable & nice.
  • I think most people have some moments when we come back to read our old code writen in contests, and have no idea what we did. Since we've been there, it's not natural to think that we would write such code when we know that we need to maintain them.

I understand that the points I made above are probably biased. So what do you think? Do you believe that being good competitive programmer correlates negatively with being good on the job?

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