On the second day of staying in the Polish capital we went for a walk in the city centre. It was cold, windy and a little rainy, so those of us who hadn't taken any warm clothes to Poland, had to buy hats, scarves and jumpers with Polish national symbols in souvenir shops. We were very impressed by the Old Town (Stare Miasto) that was destroyed in the World War II but then rebuilt. Actually, that's what comes to my mind when I imagine a historical centre of a European city: narrow sett-paved streats, clock towers with high spines, tiled roofs...

This entry begins a small account of the journey Saratov State University delegation has left for the World Finals of the ACM ICPC 2012. The destination is Warsaw, where the World Finals take place this year. The delegation members are:

• Maxim Ivanov (e-maxx), Artem Rakhov (RAD), Nickolay Kuznetsov (NALP) — the Saratov SU 2 team;
• Michail Mirzayanov, the coach, with his wife Katherine and his daughter Tanya;
• Antonina Fedorova and Tatiana Semenova, our administrators;
• and finally, me (Nerevar), as the second coach.

That is the team’s second and last journey to the finals (last year they brought silver medals from Orlando). And for me this is the first journey to the Finals not as a participant (I participated in 2009 and 2010, and was a success too).

Hello everyone,

We are glad to invite you to participate in today’s round.

Problems have been prepared by poopi, Mohammad_JRS, Gerald and me. The hero of our contest is called “PMP”. It is actually the base of our team name through the last five years. The stories are metaphoric, but they have some traces in truth.

This Codeforces round, is the last round before the incoming ICPC world final. Our best wishes for all participants of that contest, too.

I want to specially thank Gerald for his helps and advices in problem preparation, Delinur for translation of statements into Russian and MikeMirzayanov for this great system.

And we have a modified version of Burunduk1 ’s advice: “to make the round even more interesting for us, read the statements of ALL problems.” :)

We hope you enjoy the problems and have high ratings.

Update: Contest is over. Thanks to everyone for taking part and congratulations to the winners of both divisions, specially peter50216 for being the only who solved all the problems of division 1! :)

Update: Editorial

Good Morning, Codeforces!

Analyzing the task C (Div1), E (div2) I came to the conclusion that the author's solution is wrong, so I bring to you all a huge apology.

However it turned out all pretests were correct and there are only a few number of incorrect hacks (only 3). After discussing the situation with MikeMirzayanov we made ​​this decision:

• Problem E almost do not effect on contest results for Div2 participants (there are only a few number of submits and no hacks), so the contest will be rated for Div2 participants.

• The contest will be rated for Div1 participants, only if this problem have right and fast solution. I wasted all todays night (or morning) finding this solution. Therefore I propose to solve this problem by the community (if it's possible). If during the day, i.e. 24 hours after publishing this post, one cannot find solution, Div1 competition will be considered unrated.

Once again I bring you my apologies for this mistake. I hope that we will be able to master this problem together. Feel free to write all your ideas in this post, even some wrong idea may hint at the right solution. We would be very grateful to everyone who will take part in solving of that problem.

Note that this problem appeared in problemset. All tests are correct and you may try to solve it.

UPD: 24 hours have passed. Unfortunately, no one has written the correct solution, or close to it. Div1 round is declared unrated. Many thanks to all those who put their efforts and tried to solve this problem.

Best regards, Gerald Agapov.

Hello everybody! There is less than 3 hours before my second codeforces round, in which I participating as author. (The first one was — Codeforces Beta Round 56.) It will be llok like the previous one. (That was not bad, I wish. :-)!) I wish, you like today's contest.

I'm the author of this round, except one problem, which was proposed by Gerald.

In preparing this round was participating : Gerald (He always makes problems better.), cerealguy (Who helps in preparing, i think, the hardest problem of this round. He had solved the first version of round — and think, that it's easy.), Delinur (Who translate the problems). And also it was done with help of "Polygon" and "Codeforces".

I wish, you luck in this contest and to have high rating.

Problem scores will be as always. I wish, that problems are sorted well.

UPD: I'm very bad man, and have written wrong solution in problem "C". Problem under investigation.

Challenge24 finals are finally over, and as usual, I hurry to share my impressions about them. The impressions are sponsored by team Progopedia (Andrii Maksay a.k.a. maksay, Sergii Dymchenko a.k.a. kit1980 and me). Such things are the best to write immediately after the contest, while the emotions still invade you. Of course, one can start writing them while still in the competition (and last year I did so — I was pretty useless at night anyways), but this year we felt alert and fought for the points till the last minutes of the contest, so the blog post was postponed.

The main part of Challenge 24 took a bit less than 48 hours: registration and optional sightseeing on Friday, the round itself from Saturday morning to Sunday morning, and winners announcement and closing ceremony (for the toughest contestants who don't really need all that sleep) on Sunday noon.

**UPD1: ABBYY Cup 2.0 is completed! **

UPD: Editorials here. They will be updated again :)

Hey, everyone!

We remind you that today at 16 PM the first division of ABBYY Cup 2.0 starts!

This contest is rather hard to be solved completely and it is aimed at the first division Codeforces participants!

Don’t forget to register for the contest!

The duration of the contest is 5 hours. You should solve six problems (one of those is heuristic). The tests are split into three categories (easy, moderate, difficult), they are worth 20, 30 and 50 points, respectively. Only fully passing a group of tests is counted. When contestants win the same number of points, the penalty time is counted by the ACM rules. Fully solving some group of tests is counted as submitting an ACM-problem and will determine the penalty time you get. The first division (hard) contest will be a rated event for any participant despite of the participant rating and type of participation.

We hope you’ll enjoy the contest! Good luck : )

Croc Champ 2012 - Final

Final Update: Congratulations to the prize winners!

• First place: neex.emil — 100000 rubles
• Runner Up: Dmitry_Egorov — Apple MacBook Pro 15
• 2nd Runner Up: vepifanov — Apple MacBook Pro 13

Videos for the onsite round (posted by ivan.popelyshev): 1 2 3 4 5 6

Congratulations to the winners of the mixed group (onsite & offsite)!
ivan.metelsky
YuukaKazami
neex.emil

rng_58 deserves honorable mention for the only competitor to correctly submit both D and E :)

Editorial.

Hello Codeforces!

I am glad to welcome you — both onsite and out-of-competition competitors — to the final round of Open Moscow Programming Championship By CROC. I am the writer of this round — Gerald, ivan.popelyshev and Delinur helped me in the preparation of the problems. This is my second round in Codeforces, so far, thanks to the Codeforces team and MikeMirzayanov for giving me this opportunity again!

Please note that this round is held in conjunction with its onsite counterpart, so its starting time may be delayed. Also, since MikeMirzayanov is very busy with the onsite contest at the moment to decrease the load (to avoid any disaster for the onsite competition), I apologize that you may not receive any email reminder about this match.

I've taken feedbacks from my last match into account, so the pretests will be fairly strong. The match should be more interesting for you if you decide to try and solve as many problem as possible, instead of stopping and hacking other codes early in the match :)

The rules below are copied-modified from Ripatti's post:

Competition will happen by usual rules of Codeforces, with hacks and score falling in process of time. The three championship winners will be awarded valuable prizes:

• 100000 rubles for the first place
• Apple MacBook Pro 15 for the second place
• Apple MacBook Pro 13 for the third place

Please remember that the round will be rated only for onsite participants and Division 1 contestants, since the problemset may be more tricky than usual (or it may not be :) ). Division 2 coders can participate, but it will not be rated for them.

There will be five problems ordered by approximately increasing complexity. The scores will be 500-1000-1500-2000-2500. Don’t forget that during contest your solutions will be tested on a small set of pretests. Testing on full testset will be after end of the round. Pretests can don’t cover all cases of input data, so you should test your solutions very carefully.

It is strictly forbidden to publish statements/solutions of the problems before round will be end. Also you shouldn’t to talk about problems, discuss some things about possible solutions of them. Let’s be honest! You can discuss problems after the end of round.

Good luck everyone! I will be watching :)

Good Day, Codeforces!

Remember, that at 17:15 the final of the Open Moscow Programming Championship By CROC will start.

As usual anyone wishing to participate in this round can compete in it out of competition. But as this competition is quite complex, it will be rated only for participants from Div.1.

Note that this competition is closely connected with onsite competition in Moscow. So the starting time can be shifted. Watch closely for changes in the schedule.

Welcome friends)

We are glad to introduce you regular Codeforces round #117 for Div.2 participants. Everyone can traditionally participate in it.

Problems are prepared by command of authors: Pavel Kholkin (HolkinPV), Ivan Fefer (Fefer_Ivan), Nikolay Kuznetsov (NALP) and Gerald Agapov (Gerald). Thanks to Michael Mirzayanov (MikeMirzayanov) for Codeforces system and Mary Belova (Delinur) for translating problems.

And again score distribution will be dynamic) More information you can find here.

Note that all problems today will be given in random order.

Some Div.1 participants register for the contest before settings of registration were changed. Before the round it will be fixed and they will participate out of competition.

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

UPD: the statement for problem 182E - Wooden Fence was formulated incorrect, correct variant of the statement will be soon, we apologize to the participants.

UPD2: the contest is declared unrated.