Hello Codeforces!

I am glad to invite you all to participate in regular Codeforces Round #352 that will take place on 11 May, 19:35 MSK. This will be my first round, so I hope that it will be interesting for you guys. There will be 5 problems for each division, and contest will last 2 hours.

Round wouldn't take place without the help of GlebsHP, I am very thankful for his great help. I also want to thank to Zlobober, winger, AlexFetisov, ikbal and ykaya for testing problems, to hasanb for inspiring me in a problem. I got great help and wise advices from all of them so this is their round too as much as mine. Of course I want to thank Mike and all others who puts his effort into Codeforces and Polygon systems. I don't know what we would do without this great platform.

UPD1: Score distribution:

Div. 2: 500-1000-1500-2000-2500

Div. 1: 500-1000-1500-2000-3000

UPD2: I will post editorial as soon as possible, thank you for your patience. Congratulations to winners!

Div.1 winners:

1-subscriber

2-W4yneb0t

3-jcvb

4-Merkurev

5--XraY-

Div.2 winners:

1-the_arr_of_war

2-Shavkat_Aminov

3-Lightning34

4-I_Love_Ginger

5-tjandra

UPD3: Editorial is now available.

Flex your programming muscles in Yandex.Algorithm, an annual international programming championship organised by Yandex, one of the largest internet companies in Europe and Russia's leading search provider.

Anyone over 18 – regardless of education, profession or programming style – has a chance of reaching the finals and winning up to the equivalent of $4,500, while participation in the preliminary rounds is also open to younger competitors from age 6. The top 512 participants according to the cumulative result of all three elimination stage rounds will receive a contest T-shirt.

The warm-up round takes place online on May 10, starting at 21:00 Moscow time (UTC+3). It is followed by the qualification round, which takes place online on May 21 starting at 00:00 Moscow time (UTC+3), and running for 48 hours. To qualify for the elimination stage rounds you need to solve at least one problem in the warm-up or qualification rounds. The top 25 competitors after the elimination rounds advance to the finals in Minsk, Belarus.

See the schedule of all rounds here. Read more about Yandex.Algorithm and register for participation no later than May 22.

Take a look at 2015 problems and results here.

Good luck!

UPDATE 01. The warm-up round takes place tonight at 21:00 (UTC+3). You can qualify for the elimination in this round.

UPDATE 02. Analysis of the warm-up round.

Hi everybody.

The VK Cup Round 3 is coming (exact time).

The duration will be longer than usual, likely 3 hours.

As usually in VK Cup, there will be three contests — div1, div2, official one. All of them are rated. Div1 and div2 versions are for individual participants, not for teams.

Setters are Radewoosh, Errichto and qwerty787788. I think that (some) problems are extremely interesting and I really wish I could participate. Thanks to GlebsHP and MikeMirzayanov, we wouldn't have a round without them. Also, thanks to AlexFetisov and winger for testing.

We will later inform about the final duration. Maybe we will inform about the number of problems and scoring.

I wish you great fun and no frustrating bugs. And Limak wishes you good luck!

UPD

• The contest will last 3 hours.
• ADJUSTED POINTS DROP — Points will decrease with such a speed that submitting a problem at the end would give you the same number of points as in standard 2-hour rounds.
• I updated testers above.
• Top50 in the "Div1 Edition" contest will get t-shirts. Have I already said "I wish I could participate"?

UPD 2

There are 9 problems. Div2 gets problems 1 - 6, and Div1+R3 gets 3 - 9. It means that there are 4 shared problems.
Division 2: 500 750 1000 1500 2250 3000
R3 & Div1: 500 1000 1750 2250 2250 3000 3000

UPD 3

Enjoy the editorial

UPD 4

The system testing is over. Congratulations to winners. Later I will try to put winners here in some nice format.

On May, 5, 16:05 (UTC) Codeforces Round 350 is going to start! Yes, pay attention to the non-standard start time.

I took advantage of my official position and the round is expected to be a bit experimental with an expanded set of problems. Perhaps for experienced participants (sorry, Div 1) it could seem easy. This time, emphasis was placed on the main target audience of the round: so in the round will be a lot of very simple problems, but even the top of the second division will find something interesting. In addition, one of the problems will be offered in two versions — in a simplified version with small constraints and in a harder version with greater constraints. Thus, if you immediately realize solution for large constraints, you can write and submit the same code on the both version.

The problem writers are me and fcspartakm. We hope that you will enjoy the problems and the round will be fun and useful!

The expected scoring is:

• A: 500
• B: 750
• C: 1000
• D1: 1000
• D2: 500 (i.e. the complete solution of D is 1500 points)
• E: 2000
• F: 2500

Good luck!

UPD: As it was pointed in the comments we have a tricky point about hacks with problems D1/D2.

1. To avoid the situation when participant locks the problem D1 and looks the solution of the problem D2 in his room, you are allowed to lock the problems D1/D2 only together in the same time and only if both of your solutions for this problems passed the pretests. In the other words, the possibility to lock D1/D2 will appears only after you solved both problems. The problems D1/D2 will be locked together in the same moment.

2. To avoid the situation of double reward for hack of D1 and D2 of the same participant, the participant A after successful hack of the participant B on the problem D1 loses the possibility of the hack B on the problem D2. Similarly if the participant A successfully hacks the participant B on the problem D2, then A loses the possibility of the hack B on D1.

UPD 2: The round is over. My congratulations to the winners! Here are the heroes of the round.

The Top-5 among the official participants:

1. xlk200
2. TableEnterer_Lin
3. cykhhq595
4. xxxholic
5. A_Navie_Moer

The Top-5 among the unofficial participants:

1. anta
2. -XraY-
3. Um_nik
4. halyavin
5. Enchom

UPD 3: Problem analysis is now available.

Hi everyone!

May 2, 11:00 (MSK) the mirror of XX Ural Championship will take place for Open Cup participants on Yandex.Contest system.

Contest is not stage of Open Cup, but it's winner will be awarded Internet-Ural Champion's Cup. Authors are — winger, Kurpilyansky, Stigius, Erop, AlexFetisov and other Ural (and not only) veterans. Thanks to GlebsHP, TeaPot and SirShokoladina for testing and useful advices, and thanks to MikeMirzayanov for Polygon.

UPD

Contest link: https://official.contest.yandex.ru/contest/2486/enter/

UPD2

BREAKING NEWS: If you don't have login for Open Cup, you can register here: https://contest.yandex.ru/contest/2486/enter/?lang=en

UPD3

Teams without login for Open Cup should enter the contest via link above, teams with login for Open Cup — via https://official.contest.yandex.ru/contest/2486/enter/

Statements: https://www.dropbox.com/s/nrdu4jaqamqnjdp/chu-statements-en.pdf?dl=0 https://www.dropbox.com/s/xg18wiej9xm8yqw/chu-statements-ru.pdf?dl=0

Hello, all!

We are glad to announce the final version of Russian Code Cup 2016 rules! The most important news of this year is that Russian Code Cup goes international, now the problems are available in both Russian and English. Anybody can participate, to enter the competition, please register at http://russiancodecup.ru, participants of previous championships need to confirm their participation in their profile.

This year the prize pool is again 750 000 rub. We have changed the structure of the prizes to give more money prizes away, so top 25 now get cash. The winner gets 150 000 rub, the second place gets 100 000 rub, the third place gets 65 000 rub. Those who take places from 4 to 10 get 30 000 rub, and places from 11 to 25 can account for 15 000 rub. Top 200 in elimination round get branded Russian Code Cup t-shirts.

There are three levels of the championship. First you must qualify in one of the three Qualification Rounds (May 8, May 29 and June 5). Top 200 from each round proceed to Elimination Round (June 19), top 50 from it proceed to Final Round (September 18). If you fail to qualify in a Qualification Round you can still try in the following Qualification Rounds.

We invite you to the Qualification Round 1 on Sunday, May 8, 19-00 Moscow Time, and wish everyone good luck!

Hi everyone!

Yeah, you guessed it right, after a long four month break after the latest div. 1 round which was not dedicated to any official competition, you will once again have the unique opportunity to participate in usual codeforces round. No t-shirts for top-x competitors! No multi-level selection system for the opportunity to compete in final! No esoteric languages or marathon-like problems! We even will not tell you the scoring untill the very end of the round! That's it, like the good old days.

So this round was prepared for you by Ivan Smirnov (ifsmirnov) and me (adamant). We want to thank Max Akhmedov (Zlobober), Alex Frolov (fcspartakm), Edvard Davtyan (Edvard) and Mike Mirzayanov (MikeMirzayanov) for the help in round preparing, and useful advice. Special thank to Edvard for taking the role of coordinator this time and traditionally MikeMirzayanov for polygon and codeforces systems.

Good luck to everyone! We really hope that you will have a lot of fun participating in this round :)

UPD. Score distribution:

Div. 2: 500-1000-1500-2000-3000

Div. 1: 500-1000-2000-2000-3000

UPD. 2. Also thanks a lot to Alex Fetisov (AlexFetisov). Forgive me, please, I have totally forgotten about you :)

UPD. 3. If you missed the editorial, you can find it here.

April 25, 18:00 (UTC) the second Wild-card round of VK Cup 2016 will take place.

Participants are invited to achieve progress in solving an unusual problem. VK Cup teams which were advanced to the Round 2 (and didn't advance to the Round 3) will take part in VK Cup 2016 - Wild Card Round 2 officially. In addition, this round will be open to the public for unofficial participation for everybody. Registration will be open for the whole round duration.

The round will be one week long. After the end latest submission (with positive score) of each participant will be judged on system tests.

Good luck!

UPD 1: Unfortunately, it turned out that most of current tests were not various enough and did not cover different scenarios of the testing system. Tests in the system have been updated, all submissions will be rejudged. Perhaps the rejudging process will take some time. In addition, the scoring function has been updated (its monotony maintained). Because of this, points for your submissions changed a bit. The restriction on the number of submissions has been added (up to 20000). Check out the updated statement for details.