Good morning (day, evening, night)!

Today's round problems authors are we — Rei and yaro. We've been thoroughly selecting the problemset, so hope you'll enjoy the final edition.

Thanks to problem coordinator Artem Rakhov for invaluable help in round preparation, and to those, who makes codeforces more comfortable, functional and stable.

Wish you good luck!

UPD. Analysis: A B C D E

The year 2010 is over and of course, we are all ready not only to meet the Old Style New Year, which is a Russian national holiday. We are also ready to learn the names of those awarded by the Cormen Medal in 2010.

First, nomination "The Best 2010 Secondary School Contest Participant". And the winner is... (drum-roll) Gennady Korotkevich. He took part in 5 out of 6 WPS (Winter Programming School) Olympiads organized by the Codeforces and won each of them! He participated individually in the team contest, but nevertheless got ahead of all the contestants.

The Cormen Medal in "The Best 2010 Participant" nomination gets... Gennady Korotkevich! Over the previous year Gennady participated in 15 Codeforces rounds and won 5 of them. He also was among the five leaders in 9 rounds. The phenomenal success may be due to the fact that Gennady studies in the 10th grade. Bravo, tourist! Codeforces wishes Gennady to have new victories and achievements!

In the nomination "The Best 2010 Problemsetter" Natalia Bondarenko. This year Natalia spectacularly finished the career of an ACM ICPC participant (let me remind you that she got the final's golden and silver medals and won NEERC 2008). Natalia also studies in Saratov State University as a postgraduate student and is a huge help to Codeforces with organizing rounds, preparing interesting tasks. Her list of achievements includes preparing 5 contests, writing 19 tasks and helping to organize yet more. Thank you, natalia. We gladly give the victory in this nomination to you and wish you further fruitful work.

Thanks to all those who took interest in the project in the previous year. We are very glad that our contests find their participants who share their impressions on Codeforces pages.

Hello, CodeForceans!

This CodeForces Round, 50-th already, will be carried out by me, Max Ivanov (e-maxx).

I invite to this round all schoolchildren who have just returned from their training camp "LKSH.Winter" - not to give their brains an excess respite, and all students - to distract from all the troubles caused by such a fearful phenomenon as the Examinations :)

The contest is over, congratulations for the winner - RAVEman!

Problem editorials:

• problem C
• problem D
• problem E

Problem Statements:

• Russian Statements in PDF
• English Statements in PDF

The problems in this round will be five stories from a life of one Hedgehog (don't be surprised - hedgehogs are my loved creatures :) ).

Codeforces had accumulated a many interesting problems, so it time to make own problemset. So today was not in vain – I’m presenting you the problemset of Codeforces. Perhaps the only reason we need it - is to make it easier to solve problems after the contest and understand what solved, and what does not. There were request in comments. I do not think that it is important feature, but someone will be more convenient: and it was good.

Hi everyone!

The recent testing round went well. It is expected that everything will run faster. Today's round was prepared by: Mike Mirzayanov, Nickolay Kuznetsov, Ivan Fefer and Maria Belova.

Good luck!

Artem Rakhov and Codeforces team

• Problems
• Standings
• Winner: JKeeJ1e30

Hello!

Tired to rest? Your help is needed.

During the period from December 31 until today I have made many changes in the Codeforces. The changes affected only the interior, so you will not notice any change in the user interface. Nevertheless, during this time was changed about 150 project files, database schema, some principles of data storage. In short, after all this, I'm not sure that everything works as expected (although, of course, I spent time on testing). For this reason I decided to organize Codeforces Testing Round #1, which will unrated and his only goal - a comprehensive testing of the project in conditions close to the real contest.

It will be three problems (possibly well-known, folklore), but I hope it will be pleasure to solve them.

Thanks for the help to Artem Rakhov, Maria Belova, and Max Ivanov

MikeMirzayanov.

UPD: Thanks to all. The round finished. We didn't notice any bugs. Write suggestions and opinions in the comments.

Happy New Year, Happy New Code!

Let the new year bring you not only the traditional happiness, luck and health, but little programmer's delight: complete solutions, advance of (semi)finals, rating increase and absolutely no need to debug because of the perfect code. Wish you beautiful ideas and implementations!

It is usual to make presents On New Year. I do not know, what can you prepare for Codeforces (problems? articles?), and we decided that on New Year's sometimes happens what does not happen on other days. In the New Year holidays (from 31 December to 3rd January) in the user interface (Profile -> Settings -> handle) you can change your handle to any other.

Have fun celebrating the holiday,
Codeforces team

P.S. Thanks to anatoly-rr for such a beautiful calendar.

Hello!