Welcome dear friends)

We are glad to introduce you regular Codeforces round #113 for Div.2 participants. Everyone can traditionally participate in it.

Problems are prepared by known command of authors: Kholkin Pavel (HolkinPV), Nikolay Kuznetsov (NALP), Artem Rakhov (RAD). Also thanks to Gerald Agapov (Gerald) for his help, Michael Mirzayanov (MikeMirzayanov) for Codeforces system and Mary Belova (Delinur) for translating problems.

In todays contest would be one innovation. Score distribution would be dynamic. More information you can find here)

We hope that todays round would be succesful. We wish you good luck and high rating!

UPD: The contest is over. Hope you enjoy the problems) the editorial is already here)

Congratulations to winners:

1. Avalanche

2. seiya

3. Konon

4. yongheng5871

5. I_dont_have_girlfriend

6. ibra

7. Doriam30

8. unknown79

9. UESTC_Hetalia

10. lisang

CROC invites talented and innovative programmers (at least 18 years old) to participate in the Open Moscow Programming Championship. The championship is held on the basis of the Codeforces project. Saratov State University involved into jury and the technical committee. The official championship language is Russian, but the problems will be in Russian and English.

The championship will consist of qualification, two online rounds (on April 3-4, 6 and 20) and the final round that will take place on April, 27 in Moscow in the CROC Headquarters. The championship finals will also include a AI-game round.

The championship winners will be awarded with valuable prizes: the first place winner gets 100000 rubles, the second and third place winners get Apple MacBook Pro. The contestant who wins the first place in the AI-game round will be awarded with an Apple MacBook Air.

To participate in the championship, you must register on http://www.crocok.ru/championship/ (in Russian) before April 4, 2012.

You can also learn more about the project if you follow the link http://crocok.ru and click the tab called "Programming Championship".

So here goes the editorial. Note that Factor allows pretty random codes, feel free to put all words in one line, but all words must be separated by at least one space, don't try to skip a space between a bracket and a word or something like that.

162A - Pentagonal numbers

This problem was almost the same as 130A - Hexagonal numbers from Befunge round. Data input and output is done exactly as in the sample code, and besides them the program needs only basic stack operations.

USING: io kernel math math.parser ;

readln string>number
dup 3 * 1 - * 2 /
number>string print

Factor has a very system of built-in libraries which liberate the programmer from solving a lot of basic routine tasks. So after the first (trivial) probllem I gave several one-liners

The contest is over. My sincere respect to the winner in overall run nab who solved all 10 problems in 1h 25m, and congratulations to the winner in the official contest winger who repeated this heroic deed in 1h 52m.

Here is the editorial.

The language of this round is Factor — a stack-based functional language with a sophisticated system of built-in libraries (dictionaries).

Dear friends!

The next competition — Codeforces Round 112 for participants Div. 2 will take place through a pair of hours, but the others can traditionally participate out of competition. It has been prepared by a small command of authors: me (NALP), Artem Rakhov (RAD) and Pavel Holkin (HolkinPV). There were Gerald Agapov (Gerald), Maria Belova (Delinur) and Michael Mirzayanov (MikeMirzayanov) with us as always.

Especially I would like to wish good luck to my teammates Artem Rakhov and Max Ivanov (e-maxx) who recently flew to the U.S. to participate in Onsite Round Facebook HackerCup.

We hope that this problems will be pleasant to all participants and everyone will take the deserved high place in the standings :)

UPD: The contest is over, thanks to all for taking part :) We hope you have fun.

UPD: You can find the tutorial here http://codeforces.net/blog/entry/4124

UPD: Congratulations to the winners!

1. Doriam30

2. woshisb

3. Senjougahara_Hitagi

4. LiWenHaoTianXiaDiYi

5. pqxdcel

6. UranusX

7. QDkAc

You can see the full standings here: http://codeforces.net/contest/165/standings

Hello everyone!

It's time for the first round of the VK Cup 2012. Let me remind you that the registration for this round is also required and it's closed five minutes before the start.

The problemset has been developed by various authors from VK, Codeforces and Saratov State University. We worked hard to make this time interesting for competitors and to have the best ones in the next round.

This round will be run according to Codeforces rules: with room assignments, hacks and usual score decrease. It will be rated for you either if you participate in VK Cup or just solve it as a normal round.

Top 700 competitors will advance to the second round immediately. 50 more competitors will advance to the second round via the first unusual rules wildcard round on March 18.

There's one wish for everyone from Burunduk1: “Please, to make the round even more interesting for you, read the statements of ALL problems.”

Good luck and try to win!

Update: congratulations to all competitors with 1712 or higher score: you advance to the second round!

Update2: editorial is available: http://codeforces.net/blog/entry/4097

Update3: Several cheaters have been removed, the results now slightly differ. All participants with 1684 or higher score advance now to Round 2. Everyone else is invited now to the first wildcard round, the last chance to advance.

Hi everybody!

Let me remind you that on the 9th of March, at 08:00 the second qualification round of the VK Cup 2012 championship will start.

It is the last chance to advance to the Round 1. Contestants who gain a score equal to the 800-th place finisher score or greater will advance to the Round 1.

You will find a few simple problems, roughly ordered by the increasing complexity. During the qualification rounds the problems are judged only on pretests and system testing will take place after the end of the qualification round (round continues for 24 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The qualification rounds have no hacks or decreasing values of the problems.

The round will last for 24 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best men make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end. The results of the round will not affect the rating, non-competitive participation in the round is not allowed. However, all tasks will go to the archive after the end of the round.

Best of luck and enjoy solving the problems!

UPD: System testing completed, score to advance to Round 1 is 3500 3450. Congratulations to all advancers!

UPD 2: We've removed cheaters and score to advance decreased to 3450!

Good day!

We are glad to introduce you regular Codeforces round for Div.2 participants. Everyone can traditionally participate in it.

Problems are prepared by Kholkin Pavel (HolkinPV), Rakhov Artem (RAD) and Nikolay Kuznetsov (NALP). Also thanks to Michael Mirzayanov (MikeMirzayanov) for perfect system, Mary Belova (Delinur) for translating problems and Agapov Gerald (Gerald) and Alexander Kouprin (Alex_KPR) for their help.

We decide to tell you some secret about todays problems. To solve them, you wiil propably use sort algorithm)

Score distribution is standard: 500, 1000, 1500, 2000, 2500.

We wish you success and high rating!

UPD: The contest is over, the tutorial will be here soon.

UPD2: Thanks everyone for participation. We hope you enjoy your problems. Congratulations to the winners:

1. Touma_Kazusa
2. ZJUT_AA
3. wwhd
4. jikwao425
5. wtiger9999
6. Jolin
7. anmtcel
8. marspeople
9. ztxz16
10. CrazyRabbit

Special congratulation to Touma_Kazusa, who solves all problems of the round.

Hi everybody!

Let me remind you that on the 3rd of March, at 20:00 the first qualification round of the VK Cup 2012 championship will start.

You need to participate in at least one qualification round to make it to Round 1. Contestants who gain a score equal to the 800-th place finisher score or greater will advance to the Round 1. If you won't participate in the Qualification Round 1 or if you failed to advance to Round 1 by its results, than that's not a problem — you can have a try at the Qualification Round 2 on March, 9.

At each qualification round you will find a few simple problems, roughly ordered by the increasing complexity. During the qualification rounds the problems are judged only on pretests and system testing will take place after the end of the qualification round (round continues for 24 hours). The pretests do not cover all possible cases of input data, test your programs carefully! The qualification rounds have no hacks or decreasing values of the problems.

The round will last for 24 hours, but it does not mean that we encourage you to spend all this time solving of problems. We hope that most participants will cope with the problems (or with most problems) in a shorter period of time. This duration of the round is chosen so that each participant could find a convenient time to participate.

Before the end of the round it is strictly forbidden to publish the problem statements/solutions/any thoughts and ideas about them elsewhere. It is forbidden to talk about the problems, discuss the statements and so on. Be honest and let the best men make it into Round 1. When the Qualification Round is over, you can discuss the problems and solutions.

You can register for the round at any time up to its end. Yes, we had a false start with registration of the qualification. We haven't switched on the Championship participant registration check function. If someone managed to register to the round on the 2nd of March, please do it again.

The results of the round will not affect the rating, non-competitive participation in the round is not allowed. However, all tasks will go to the archive after the end of the round.

Best of luck and enjoy solving the problems!

UPD: The round is over. 12907 submissions to be judged on system tests!

UPD 2: System testing completed, the final results are available.

Hello!

Welcom to the todays round! Note that this is last possibility to training before VK Cup on Codeforces — don't miss your chance! I hope, everybody will find interesting problems for him, you will not have misunderstanding with statements and there will have a harmony beteen your your solutions and our tests.

I'm an author of todays round. My name is Valeriy Samoylov, a graduated student of SPb SU. I want to thank Artem Rakhov (RAD) and Gerald Agapov (Gerald) for great help in investigation of problems.

And so I want to thank Maria Belova for translation of the statements and Alexanber Kouprin (Alex_KPR) for the statement prereading and the picture =)

Please, pay attantion to unusual problems cost in the first division:

500 — 1000 — 1500 — 2500 — 2500

And without surprise in the second division:

500 — 1000 — 1500 — 2000 — 2500

Good luck for all!

Round is postponed to 30 minutes by technically reasons. Registration is ending in 21:25.