Hi everyone!!!

It remains less than 10 hours before Codeforces Beta Round #98 (Div. 2). This round was prepared for you by me, proposed the ideas of the problems. Traditionally, RAD made sure that there is no bugs and that the statements are normal, and Delinur translated the statements into English. Thanks to them!

If you decide to participate in the round you have to help the boy Polycarpus and his classmate Innocentius in all the difficulties they face. The more you help them, the higher you will be placed in the standing.

I hope the problems will be interesting not only for Div. 2 participants, but the participants rated higher than 1699.

I will continue the story about myself (beginning of story in the previous blog entry). Besides programming I love sports. Within a few years before I started writing code, I was seriously involved in rowing. And before that I was going in for almost all sports :-): karate, soccer, hockey and so much more interesting. Now I love (especially at the training camp) to play volleyball and table tennis. I decided to prepare this round despite the fact that during the past two weeks, much has changed inside Codeforces and I took part in this.

Following the fashion trends I have changed my avatar.

Good luck for all on the round!

UPD:

Contest is finished, results are final, ratings are updated.

Top 10 (Div. 2)

Congratulations to winners!!!

Here is the editorial of Codeforces Beta Round #97. If you have any questions or suggestions --- feel free to post them in the comments.

136A - Presents (A Div 2)

A. HQ9+

The problem described HQ9+ programming language and asked whether the given program will print anything. Given the extraordinary simplicity of the language, it was enough to check whether the program contains at least one of the characters H, Q and 9.

Codeforces Beta Round #96 will take place on Saturday, December 3rd, and it will be my first classical Codeforces round. To smoothen the transition between Unknown Language and known ones, I've made the problems of the round follow a certain topic, which is of course programming languages :-)

Thanks to MikeMirzayanov, maksay и RAD for their help in preparing this round.

Good luck!

P.S. Points cost for problems: division 1 — 500-1500-1500-2000-2500, division 2 — 500-1000-1500-2500-2500.

December 11, 2011 Youth Research Society "Q-BIT" and the Department of Information Systems, Kharkiv National Economic University, conducted a traditional Kharkov Open Championship on sports programming.

Registration for the competitions:

• for onsite participants to December 5, 2011
• for online participants to December 10, 2011
  

Stay tuned for news on the site http://qbit.org.ua!
More information about the championship on the official website of the Championship http://khcup.qbit.org.ua

Informal unrated contest Codeforces Testing Round #3 is scheduled on December, 2 (Friday), 15:00 (UTC). We will test the latest innovations on Codeforces that they do not affect the contests. If not, we will fix it quickly :) So, this round will take place "as is", no warranty about it.

Problems for the round may be famous to someone, but I'll try to make them such not for any of you. It will be 3-4 problems, as quite simple and something more tricky. The contest duratiuon is 1 hour.

I say thanks in advance to all those who will come and test the system. Thank you!

The ACM-ICPC Northeastern European Regional Contest 2011 is over. Congratulations to the winners! I especially want to mention the team that will represent our region on the World Finals in Warsaw:

1. SPb NRU ITMO 1 (Kapun, Kever, Nigmatullin) — 1-st place, champions
2. Moscow SU 1 (Fedorov, Kaluzhin, Rogulenko) — 2-nd place
3. Belarusian SU 1 (Bahdanau, Pisarchyk, Sobol) — 3-rd place
4. Saratov SU 2 (Ivanov, Kuznetsov, Rakhov)
5. SPb SU 1 (Andreev, Boykiy, Fondaratov)
6. Moscow IPT 1 (Dlugach, Gimadeev, Shishkin)
7. Ural FU 1 (Dolgorukov, Schelkonogov, Soboleva)
8. Altai STU 1 (Silin, Uvarov, Yesipenko)
9. Ufa SATU (Lezhankin, Mazgarov, Ripatti)
10. Nizhny Novgorod SU (Lyulkov, Shmelev, Vadimov)
11. Belarus SUIR 2 (Berezhnov, Brukau, Ropan)
12. Udmurt SU (Abizyaev, Kibardin, Urbanovich)
13. Latvian U 2 (Kalinicenko, Vihrovs, Vilcins)
14. Kazakh-British TU 3 (Aitbayev, Satylkhanov, Almakhan)
15. Tomsk SU 1 (Chadnov, Kolupaev, Afanasev)
16. Volgograd STU (Agafonov, Chalyshev, Zhorin)

Codeforces wishes all future World Finals participants the success in preparing for the competition and good results in the final!

Hello!

On Friday, November 25 at 19:00 I'm waiting you on the Codeforces Beta Round #95 (Div. 2). This round is prepared by me. It is not easy to prepare a round, but it is always useful and interesting. By my example, I want to hint to top participants that rounds of famous people — it's always interesting!

Apart from me RAD, Nickolas and Delinur were doing work on the round. Moreover, Edvard still do not know, but very soon I will ask him to solve this round as a tester:)

It will be unusual round because you will find six problems. It's a little experiment — I hope that it will help each participant to find interesting problems to themselves.

I believe that the out-of-competition participants from Div.1 will have some fun solving the round.

The problem scoring is: A - 500, B - 1000, C - 1500, D - 2000, E - 2500 and F - 2500.

Good luck!

MikeMirzayanov

UPD. The competition has ended. Here are the results. First place was taken by the representative of China — liuq901. Congrats! It was nice to see such interest to the contest. Thank you for your participation!

Unfortunately, I do not have the opportunity to write a tutorial. If you deal with it I will be grateful.

So here goes an editorial for the round. For me Befunge is one of the languages in which it's much easier to write code than to read it (and debugging code written by someone else is a complete torture; that's why we don't have hacking in ULRs). That's why I'll post just the general idea of the solution and my own codes — the latter just to show that I can code in Befunge too.

A. Hexagonal numbers

&:2*1-*.@

A "consolation" problem, which requires only to understand the principles of working with stack. Read n, duplicate it, multiply the topmost copy by 2 and decrement the result. Now the stack contains two numbers n and 2n - 1; multiply them and print the result.