By fcspartakm, history, 2 days ago, translation, In English,

Hello, Codeforces!

I'd like to invite you to Codeforces Round #354 (Div. 2). It'll be held on Wednesday, May 25 at 18:05 MSK (Moscow time) and Div. 1 participants can join out of competition. As usual round starts in the unusual time!!!

Me an Grigory Oxxxymiron Akhremenko prepared the tasks for this Round. It is the debut for Grigory as the problemsetter.

Great thanks to Gleb GlebsHP Evstropov for helping us preparing the contest, to Mike MikeMirzayanov Mirzayanov for the great Polygon platform and for Ilya IlyaLos Los and for Artur ikar Svechnikov for writing solutions.

The scoring distribution will be announced later. Good luck everyone!

UPD Score distribution 500-1000-1500-2250-2250

UPD2 Editorial

UPD3 Congratulations to the winners

  1. Thomas66

  2. super_wormy

  3. Valkata.a.k.a.TheHacker

  4. tcchung

  5. Karakotov

UPD4 See you soon!=)

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By Chmel_Tolstiy, 6 days ago, translation, In English,

Yesterday ACM ICPC World Finals finished. We congratulate all winners, medalists and special prize winners!

We want to remind you that tomorrow, May 21, at 00:00 (UTC+3) the qualification round of Yandex.Algorithm will start. For participation in qualifications you should register and start a virtual contest at any time prior to May 23 (UTC+3).

As usual 6 problems of varying difficulty will be provided at Yandex.Algorithm rounds. In order to qualify for the elimination stage rounds and compete for a trip to the finals in Minsk and other prizes you should solve at least one problem.

Also Yandex.Algorithm offers students to participate in the internship track. For more information see the rules of the championship.

Good luck! See you at Yandex.Algorithm!

P.S. The qualification round has started. Problems prepared by Romka, Ixanezis and Chmel_Tolstiy.

EDIT. Analysis has been posted.

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By MikeMirzayanov, history, 8 days ago, translation, In English,

ACM-ICPC World Finals 2016 will take place on May, 19, 03:00 (UTC). It is one of the most important events in programming competitions life.

More than 40000 contestants from 2736 universitites from 102 countries had competed in regional competitions. 128 teams had advanced to the World Finals, which are held this year in Phuket, Thailand. Soon we will know which university takes home the most prestigious title in programming — the tile of the World Champion of ACM ICPC!

Useful links:

I wish the teams good luck and many baloons!

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By MikeMirzayanov, 8 days ago, translation, In English,

The Finals of ACM-ICPC 2016 in full swing! Teams and organizers gathered in Thailand. The weather is fine — heavy showers at nights, hot days. The rainy season is in action. Here it is about two a.m. now, but as I absolutely can not sleep, I decided to share my impressions and photos from the first two days of the main event.

This year, the teams' resettlement delivers certain inconveniences — teams and coaches live in the same hotel, and all the other members of the delegation live in another. The first hotel (Le Meridien), is probably a bit better — own way out to the ocean and pool make everybody to envy those who lives in the Mövenpick (yes, like an ice cream).

Le Meridien, photo from the official hotel website

Buses ply between hotels, you need an hour to go. A bit uncomfortable that the buses do not run every day, or at least not always, only as scheduled.

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By komendart, history, 11 days ago, translation, In English,

Hello, everyone!

Codeforces Round #353 (Div. 2) will take place tomorrow on the 16th of May at 19:35 MSK. I tried to make interesting problems, hope you enjoy them.

I'd like to thank GlebsHP for his help in preparing problems and MikeMirzayanov for Codeforces and Polygon.

Good luck!

UPD Scoring 500-1000-1500-2000-2500

UPD Editorial

UPD Congratulations to winners!

Div. 2

  1. NovaBlast

  2. Salvare008

  3. orzchimo

  4. student_hh

  5. Pain_Konan

Div. 1

  1. ksun48

  2. sugim48

  3. KrK

  4. cgy4ever

  5. nfssdq

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By muratt, 2 weeks ago, In English,

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:






Div.2 winners:






UPD3: Editorial is now available.

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By Chmel_Tolstiy, 4 weeks ago, translation, In English,

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.

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By Errichto, 3 weeks ago, In English,

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 Stonefeang, 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!


  • 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"?


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


Enjoy the editorial


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

VK Round 3 Div. 1 Div. 2
1. subscriber, tourist 1. Endagorion 1. Bus
2. eduardische, Alex_2oo8 2. eatmore 2. Herzu
3. AlexDmitriev, Kostroma 3. ikatanic 3. co_farmer
4. LHiC, overtroll 4. izrak 4. TDL9
5. KAN, vepifanov 5. rowdark 5. polingy

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Announcement of VK Cup 2016 - Round 3
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By MikeMirzayanov, history, 3 weeks ago, translation, In English,

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. sorry_liao772002
  4. Parfait
  5. A_Navie_Moer

The Top-5 among the unofficial participants:

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

UPD 3: Problem analysis is now available.

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