We are glad to welcome all contestants of a qualifying contest "Yandex.Algorithm 2011 - Round 1".

Today's round authors are Vitaly Goldshteyn, Ignat Kolesnichenko, Stanislav Pak and Denis Yarets. All we are employees or interns of Yandex. We really appreciate Artem Rakhov, Maria Belova and Mike Mirzayanov who helped us to prepare the contest. We hope that our tasks will be quite interesting and you will get much fun solving them.

As you may know top 200 contestants after this round will be able to continue fighting for spots in the final round.

Please pay attention that as well as during the previous qualifying round Codeforces functionality will be a little cut down for the time of the competition. Do not worry, all will return into place after the end of the round.

Round will be rated for the official participants, and for those who failed to qualify and participate out of competition (unofficial).

Welcome to Codeforces Beta Round #72.

Hello!

Now you can view rating statistics for specified country and/or city on the ratings page. But there are also separate pages for rankings of the countries and the cities themselves (links to them are in the sidebar "Top rated").

Rating of a country (city) depends on participants ratings from a country (city) and calculated by the following simple formula:

where N is a minimum of 100 and number of country (city) participants, and K = 0.75.

I'm glad to welcome all fans of programming!

The second qualifying round Yandex.Algorithm will take place today, and it was prepared for you by Artem Rakhov, Michael Mirzayanov and me.

Please pay attention that as well as during the previous qualifying round Codeforces's functionality will be a little cut down for the period of the competition. Don't worry, all will return into place after the round termination.

I remind the best 500 participants pass in Yandex. Algorithm 2011 Round 1 which will take place on May, 20th at 19.00

Good luck!

Hello.

This round will start Yandex.Algorithm 2011. The problems of the round were prepared by me, of course, with the help of the Codeforces team and Yandex.

I hope you enjoy the problems and their solution will start a successful performance at the tournament.

As you have already noticed — the system operates in a somewhat truncated form. We decided to run it in safe mode and turn off some functionality at the time of the contest. After the round everything will be back.

I recall that the top 500 participants will receive a ticket to the first online round of the Yandex.Algorithm. However, if you do not get to qualify at this time, do not despair — you can participate in the second qualification, which will be held on May 6 at 15:00 (UTC).

I wish you have a fun,
MikeMirzayanov

We are glad to introduce Yandex open programming competition "Yandex.Algorithm" hosted by Codeforces. The competition starts on May 4th and will consist of two qualification rounds, two online rounds and a final onsite round. Some of the rounds are created by Yandex employees. The onsite round will be held at the Yandex Summer School in Distributed Computing in Moscow Institute of Physics and Technology.

Any registered member of Codeforces can participate. There will be 5 rounds, 2 hours each. 15 winners of the last online round will be invited to participate in the Summer School and in the final round of Yandex.Open. 70 best participants will get T-shirts.

UPD:

Editorial (A,B,C,D,E)

Hello!

As you have already noticed the menu will link to the results of the competition has appeared. Drum roll, fanfare, applause, and the blinding spotlight! We congratulate the winners:

• Winner is Aleksey, 33 score points!
• The second place — mrButt, 30 points
• The third place — Sanya_M, 29 points
• The fourth place — Ruslan, 25 points
• The fifth place — MaxBuzz, 24 points

Congratulations to all winners! Note that the program by Aleksey has surpassed all expectations of the jury erred solely on hard-to-recognize archives.

I'm asking all winners to send me a private message, we have something to discuss.

MikeMirzayanov

UPD: One test has been found in which the author's answer was incorrect. I've rejudged solutions, but the order of participants has not changed :)