Codeforces celebrates 8 years! We are pleased to announce the crowdfunding-campaign. Congratulate us by the link ×

By KAN, 14 hours ago, translation, In English,


Tomorrow, on March 17th, 2018, at 15:35 UTC the first Wild-card Round of VK Cup 2018 will be held. Along with it we will host a parallel unofficial round in which everyone can take part.

The rounds will use special rules, the rounds will be unrated. The problems were prepared by Codeforces team: fcspartakm, MikeMirzayanov and me. Thanks to Vovuh, GreenGrape, neckbosov, glebodin and gritukan for testing the round and their help to make the round better!

The detailed rules will be added to this post around 30 minutes before the start. There will be 24-hours open hacks phase after the round, like in Codeforces Educational Rounds.

Good luck!

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By Endagorion, history, 4 days ago, translation, In English,

Hello everyone! Today, on March 13 at 9pm MSK the second qualification round of Yandex.Algorithm 2018 tournament will take place. You can get to the contest page from the Algorithm site.

The problems are by me, Mikhail Tikhomirov. I am grateful to Gleb GlebsHP Evstropov for his help with problems preparation, and also ifsmirnov, halyavin, kuzmichev_dima, scorpion for testing the problems.

Good luck, see you at the competition!

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By majk, 9 days ago, In English,

The round 1 of VK Cup 2018 will take place on March 10 at 18:35 MSK (check your timezone). The contest "VK Cup 2018 — Round 1" is for teams qualified from two Qualification Rounds. The top 400 teams will advance to the Round 2, along with teams that qualify in the Wild Card Round 1 a week later. As usual, there will be two parallel rounds for those ineligible to participate in VK Cup, one for each division.

I'd like to thank KAN for steering my crazy ideas into a coherent unit, the coordination and also for suggesting one of the problems, AlexFetisov, qwerty787788, winger, Errichto, Tommyr7 and misof for testing the problems, MikeMirzayanov for building Codeforces and Polygon and VK for organising the contest.

All three rounds last 2 hours, and all are rated. The VK Cup and Div. 1 will have six identical problems while the Div. 2 contest will consist of five problems. The scoring distribution will be announced before the contest.

The main heroes of this round will be Alice and Bob. Beware that Eve might attempt to foil their plans.

This is my first round on Codeforces and hopefully not the last. Wish you many submissions, high hacks and successful rating.

UPDATE: The scoring in Div.1 and VK Cup round 1 is 500-1000-1500-1750-2250-3000. For Div.2, it is 500-1000-1500-2000-2250.

UPDATE2: The round is finished. I hope you enjoyed it. Tune in a bit later for editorial.

UPDATE3: Congratulations to winners!



VK Cup

UPDATE4: Editorial

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Announcement of VK Cup 2018 - Round 1
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By craus, history, 8 days ago, translation, In English,

Hi all.

I want to introduce you a small game I made about codeforces.

It is web game. Here is the link:

Also created a "More games" section there, if you would be interested in my other games. I love making them. One was released on Steam yesterday. You can сheck it out as well.

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By Zlobober, 9 days ago, translation, In English,

Hi everybody,

Today there will be the first day of Moscow Open Olympid, that is the personal programming competition that is held in Moscow each spring. This contest is prepared by Moscow Olympiad Scientific Committee that you may know by Moscow Team Olympiad, Moscow Olympiad for Young Students and Megapolises Olympiad (rounds 327, 342, 345, 376, 401, 433, 441, 466).

Open Olympiad consists of the most interesting and hard problems that are proposed my a wide community of authors, and that is why we decided to give you an opportunity to crack the complete problemset of the contest by making some kind of an experiment. Tomorrow we are going to conduct a rated Codeforces round based on problems of both days of our Olympiad.

We kindly ask all the community members that are going to participate in the competition to show sportsmanship by not trying to cheat in any manner, in particular, by trying to figure out problem statements from the onsite participants. If you end up knowing some of the problems of Moscow Open Olympiad (by participating in it, from some of the onsite contestants or in any other way), please do not participate in the round. We also ask onsite contestants to not discuss problems in public. Failure to comply with any of the rules above may result in a disqualification.

Round will happen at 11:05, March 9th, Moscow time and will last for 2.5 hours. There will be 6 problems in each division.

Round problems were prepared by ch_egor, sender, flyrise, _kun_, malcolm, grikukan under supervision of your humble servant with a great help of _meshanya_, GlebsHP, Endagorion and Helen Andreeva. Some of the div2 problems were finalized with help of Codeforces team represented by fcspartakm, also we would like to thank round coordinator KAN for his help in deciding which problems to take and all the discussions.

Good luck everybody!

UPD: Announcement email contained incorrect start time. Instead of "12:05, March 9th, Moscow time, 2 hours" it should be "11:05, March 9th, Moscow time, 2.5 hours", as was originally in the round announcement.

UPD2: Round is postponed by 10 5 minutes. Stay tuned :)

Congratulations to the winners!

Division 1:

  1. dotorya
  2. Swistakk
  3. Syloviaely
  4. zscoder
  5. dreamoon
  6. SkyDec
  7. Marcin_smu
  8. yutaka1999
  9. Kostroma
  10. Will_Dearborn

Division 2:

  1. _ChenKerui
  2. Demerzel_IV
  3. 879333752
  4. yyc_jm
  5. Anson529
  6. iotang
  7. wcz112
  8. Hankpipi
  9. cyz666
  10. wwd2075

UPD3: Finally, the editorial is there! Kudos to gritukan and ch_egor for making it appear in a text form.

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By BledDest, 13 days ago, In English,

Hello Codeforces!

On March 06, 18:05 MSK Educational Codeforces Round 39 will start.

Series of Educational Rounds continue being held as Harbour.Space University initiative! You can read the details about the cooperation between Harbour.Space University and Codeforces in the blog post.

This is a special Educational Round — Top three contestants among those who are eligible for participating in ACM ICPC will be invited to attend the Hello India x Russia Programming boot camp under the Codeforces + SDV banners, on a full team sponsorship.

Social Discovery Ventures (SDV) creates, develops and funds Internet projects specialising in communication platforms that enable people across the world to get closer and expand their social networks.

The winners will be fully sponsored with their boot camp participation fees, accomodation, and meals for the India location!

This round also has a special regional prize — the company Phaze Ventures, a platform founded to transform the region by unlocking the untapped potential of our youth, startups and corporates, will be sponsoring the top 3 participants of this round from Oman (also among those who are eligible for ACM ICPC) — further sharing the importance of supporting talented programmers and sending them to these types of events throughout the world.

The round will be rated for Div. 2. It will be held on extented ACM ICPC rules. After the end of the contest you will have one day to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 7 problems and 2 hours to solve them. Problem authors are PikMike, Vovuh and me.

Good luck to the participants! Hope you will enjoy the contest.

UPD: The tutorial has been published.

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By KAN, 13 days ago, translation, In English,

Hello everybody!

Today, on March 4th 2018 the final round of Technocup olympiad for Russian-speaking high school students is held. The round starts at 11:30 Moscow time.

After the round starts, you can watch the current results.

For those who want to compete on the same problems, we will host two Codeforces rounds: one for the first, and one for the second division. The rounds will start at 15:35 UTC, don't miss them!

If you compete in the Final Round today, you can't compete in the rounds at evening.

The problems are prepared by Endagorion, komendart, syncopate, AndreySergunin, fcspartakm, MikeMirzayanov and me. For testing the problems many thanks to demon1999, Belonogov, gritukan, adedalic, BudAlNik, GreenGrape, Ne0n25! Also many thanks to gritukan for his help in hosting the round at Codeforces!

P.S. Because of the olympiad, some Codeforces features may be disabled today.

Good luck!

UPD: Congratulations to Technocup winners!

  1. qoo2p5
  2. dima_z
  3. 300iq

Congratulations to winners of Codeforces rounds!

First division:

  1. V--o_o--V
  2. Petr
  3. Merkurev
  4. Benq
  5. dotorya

Second division:

  1. Deanamic_Programming
  2. kiber
  3. shad0w_walker
  4. Vitalya
  5. leedsjays

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By lewin, history, 2 weeks ago, In English,

Hello everybody!

On Mar 3, 10:00 Moscow time, Round 1 of Yandex.Algorithm 2018 competition will take place. I wrote the majority of the problems in this contest, with some additional help from GlebsHP.

I would like to thank GlebsHP for all his help with coordinating this round, MikeMirzayanov for polygon, and of course, everyone who took the time to test this round.

See you in the competition soon!

Editorial here:

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