Hello!

I'm, Valeriy Samojlov, graduating student of SPbSU,  present you codeforces beta round 79. Today you will meet with boy Gerald and will help him to solve some living problems. 

Today we have usually cost of problems in both divisions: 500 - 1000 - 1500 - 2000 - 2500.

It my first codeforces round, I hope, problems will be interesting.

I want to thank Artem Rakhov (RAD) for big help with preparation of problems, Makar Krasnoperov (Connector) for some useful remarks and Maria Belova for translation.

Good luck for participants of both dovisions!

Contest is over! Congratulation to winners!

Division 1:

1. RAVEman

2. ilyakor

3. ACRush

Division 2:

1. SuperLight

2. xiaowuc1

3. Timur_Sitdikov

Editoral a appeared.

Hi all!
Unknown Language Round #3 is going to take place on 30th of July. (This very Saturday -- Friday for some parts of the world)
This is the third contest of its type. The rules are easy (and fun):

1.     Scoring is similar to that of ACM-ICPC.
2.     The contest is not rated.
3.     You can submit your code using only one language. This language is a secret and will be announced only when the contest begins! (We'll expect lots of coding bugs and syntax mistakes!)

Congratulations to Petr Mitrichev (Petr), the Yandex.Algorithm 2011 Champion!

Congratulations also to Dmitry Dzhulgakov (dzhulgakov), Makoto Soejima (rng_58), Ivan Metelsky (ivan.metelsky), Alexey Levin (levlam) and Gennady Korotkevitch (tourist) who placed 2, 3, 4, 5 and 6 respectively! They solved as many problems as the champion. Full results are available here

Problems turned out to be really difficult: nobody managed to solve more than 3 problems during the 2 hours of competition. Problem A was considered much simpler than all others by the contest authors, but less than half of participants could solve it, and even the champion lacked 30 seconds to fix the last bug. Only one coder could solve problem E: Xhark from Korea.

Problem E was suggested by Ilya Kornakov (ilyakor) who is also a developer in my group at Yandex :) Problem A about domino and a guy named Gena was powered by Ivan Popelyshev (ivan.popelyshev). Problem B — Stanislav Pak, C — Denis Yarets. All three are also our employees. Problem D was suggested by Artem Ripatti. My problem was rejected at the last minute, so it will wait for you at the Petrozavodsk training camp :)

Thanks to all finalists, authors, participants out of competition, contest organizers, MIPT for the accomodations and the main sponsor — Yandex.

Good luck to everybody who competes in the OpenCup onsite today!

Petr and our foreign guests rng_58, wata and dolphinigle

ivan.metelsky, MikeMirzayanov and pieguy

Hi everybody!

Yandex.Algorithm finalists were gathering in Dolgoprudny... Everybody in their own unique way :)

dzhulgakov, pieguy, levlam and Progger turned out to be the most organized and arrived at the start of the Summer School. They've already socialized with other participants and began solving and competing in the practical bioinformatics problem using a distributed Hadoop cluster accessible for all school participants — good for them! Two Japanese buddies rng_58 and wata landed at Sheremetyevo airport on July 13 at 17.55, and an hour later they were already receiving their badges from me. Their fellow-countryman LayCurse mixed up the dates and took the tickets for the same flight but for July 14 :) tourist with his father came in the morning on July 14th, and dolphinigle landed yesterday late in the evening and told me I was the first man in Russia he met who spoke English :) ivan.metelsky "burst" into the room of the School organizers sleeping after yesterday's party at 8 AM; he got there himself without any instructions :) e-maxx arrived at Moscow by train at 10.38 in the morning and made his way directly to the competition with our other friends from Saratov - with some adventures on the way: the electric trains to Dolgoprudny have a break from 11.10 till 13.40. ktuan decided last minute that he won't spend his last univercity vacation for the finals, and Burunduk1 seems to have been too busy with teaching high school students and didn't answer my e-mails and phone calls (tut-tut, Sergey!) — I wonder whether he will be coming last minute. Petr will drive here from Moscow just before lunch. My intern zeliboba studies at MIPT and lives in the same building where all the other participants of the Summer School, so he'll probably come to the contest floor last :)

Everybody can register and participate in the round as usual. Those who don't participate in the onsite round will be out of competition, but the round is rated for everybody in Div-1.

I remind you that the contest time is unusual today: we will start at 16.00 The problems are harder than usual in Div-1 today — looking forward to a bitter struggle!

Update: full results

Hi all!

My name is Alexey Dergunov, and I'm glad to present you the first "violet" Codeforces round. I hope the problems will not seem so "violet" to you :)

Many thanks to following people who helped me a lot with contest preparation:

• MikeMirzayanov (Mikhail Mirzayanov)
• RAD (Artem Rakhov)
• Connector (Makar Krasnoperov)
• anonymous (Anonymous)
• Delinur (Maria Belova)
  

• 1st place - rng_58
• 2nd place - hos.lyric
• 3rd place - ilyakor

• 1st place - pmnox
• 2nd place - muliguishou
• 3rd place - craus

Hello everyone.

Today I am an author of the contest. This round is for both divisions. There will be five problems in each division. This is my second round on the Codeforces. The actors in this contest will be walruses again =)

I want to thank Codeforces and Alias for helping me to prepare the round.

Good luck!

UPD1:

Points for problems in div1: 500-1000-1500-2500-2500

Points for problems in div2: 500-1000-1500-2000-2500

Analysis 

Hello everyone!

I am an author of problems of today round. This round is for both divisions. There will be 7 problems, the first 5 of them are for the second division and the last 5 are for the first one.

About points of problems. Today they are nonstandard:
for div2: 500-1000-1500-2000-2000
for div1: 500-1000-1000-1500-2500
Be careful.

RAD helped me for preparing the round. Delinur translated statements into English.

Good luck ans have fun.

UPD.
 winners of the first division
1. peter50216
2. tourist
3. ACRush

winners of the second division
1. iamcs1983
2. zyx3d
3. seanwupi

Editorial.

UPD.
Unfortunately, in author's solution of priblem E some bug was found. We thanks participant LinesPrower for detection of it. Author's solution was updated and all solutions were rejudjed. Ratings will be recalculated for all participants excluding Egor and Jacob. We apologize for this incident.