Hi everyone!

On this Saturday I'm giving a lecture on Fast Fourier Transform on Moscow International Workshop ACM ICPC. Due to this I wrote lecture notes which anybody can use as reference for Fast Fourier Transform. I added there almost anything one should need while using FFT in contests. Even if you suppose you know the algorithm I dare you to look this paper through since there still can be some new ideas for you. Also you can see Russian version here.

Hello Codeforces!

Round will start on Thursday, 3 November in 19:05 MSK.

Tasks are prepared by Anton Garder (.tx) and me, Shpakovskiy Denis (Denisson). Thanks to 300iq, Glebodin, FalseMirror, cdkrot, Arpa, Starcall for testing problems, vintage_Vlad_Makeev for coordination and translation, MikeMirzayanov for Codeforces and Polygon platforms.

You will have six problems to solve in 2.5 hours.

Hope you will enjoy problems. Good luck to all!

Scoring: 500—1000—1500—2000—2500—3000

We want to apologise for mistakes in problem statements that led to round being unrated

Editorial.

Hello Codeforces!

On October 27, 17:05 MSK Educational Codeforces Round 31 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.

The round will be unrated for all users and 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 6 problems and 2 hours to solve them.

The problems were prepared by Ivan BledDest Androsov, Vladimir vovuh Petrov, Alexey Perforator Ripinen, Mike MikeMirzayanov Mirzayanov and me.

Good luck to all participants!

Congratulations to the winners:

Congratulations to the best hackers:

259 successful hacks and 368 unsuccessful hacks were made in total!

And finally people who were the first to solve each problem:

UPD: Editorial is uploaded

Hello everybody!

Round 443 will start on Thursday, 26 October in 17:35 MSK.

Tasks are prepared by me, Konstantin Khadaev. It's my first round on Codeforces. Thanks to zemen, AlexFetisov, vepifanov, and Belonogov for testing problems, KAN for coordination, and MikeMirzayanov for this site and the Polygon platform.

Both divisions will have five problems to solve in two hours.

Scoring: in Div 1: 500 — 1250 — 1250 — 2000 — 2500, in Div 2: 500 — 1000 — 1500 — 2250 — 2250

Good luck to all!

UPD1: Congrats to the winners!

Div 1:

1. dotorya — solved all problems!
2. Um_nik
3. jqdai0815
4. V--o_o--V
5. Errichto

Div 2:

1. monsoon
2. belkka
3. Roooooo
4. stasio6
5. AngusRitossa

Hi, Codeforces!

On monday, October 23rd, at 18:35 MSK rated Div. 2 round will be held. Participants from first division can take part out of competition.

The problems for this round were prepared by me. Thanks to Daniil (qoo2p5) Nikolenko, Nikita (FalseMirror) Bosov, Alexander (Alladdin) Proskurin, AmirReza (Arpa) PoorAkhavan, Ildar (300iq) Gainullin, Alexey (ashmelev) Shmelev for help in preparations and testing problems, Ann Izyumova for help with translation, Nikolay (KAN) Kalinin for the round coordination and Mike (MikeMirzayanov) Mirzayanov for amazing platforms Codeforces and Polygon.

You will have 2 hours for 6 problems.

Hope you will enjoy problems! Good luck!

Upd1: Editorial

Upd2: Congratulation to winners!

Div1

1. Farhod
2. vintage_Vlad_Makeev
3. KrK
4. rajat1603
5. chemthan
6. Barichek

Div2

1. wzp666
2. isybuq154
3. SORONGON
4. Sheng_D_Bao
5. wxh010910

Hello!

ACM-ICPC Southern Subregional Contest (NEERC/Northern Eurasia) 2017 has ended on October 18. There were 73 teams onsite in Saratov, most of them were invited because of their result on the qualification stage.

On Saturday, October 21, 08:05 (UTC) will start online-mirror 2017-2018 ACM-ICPC, NEERC, Southern Subregional Contest (Online Mirror, ACM-ICPC Rules, Teams Preferred).

I invite ACM-ICPC teams and individual participants of Codeforces competitions to take part! Sure, the contest will be unrated.

MikeMirzayanov

Hi everybody,

Lasts Sunday there was a 15th Moscow Team Olympiad, high school students competition based in Moscow that is an elimination contest for All-Russian Team Olympiad. This contest is prepared by Moscow Olympiad Scientific Committee that you may know by Moscow Open Olympiad, Moscow Olympiad for Young Students and Megapolises Olympiad (rounds 327, 342, 345, 376, 401, 433).

Round will be held at 11:05 UTC on Monday and will last for 2 hours. Each division will consist of 6 problems.

Problems are prepared Andreikkaa, Sender, Flyrise, mingaleg, kraskevich, wilwell under supervision of your humble servant with great help of GlebsHP, meshanya, Endagorion and Helen Andreeva.

Discussing problems with anybody who was a participant of Moscow Team Olympiad is strictly prohibited and may be a reason for disqualification.

Good luck everybody!

UPD: Thanks everybody for participation, congratulations to round winner!

Div1 winners:

1. fateice
2. simonlindholm
3. Haghani
4. sunset
5. Petr

Div2 winners:

1. Cypi
2. Nu11
3. zjt_is_our_red_sun
4. GXZlegend
5. Senji

Editorial will be published today after a while.

UPD2: Editorial!

Codeforces Round 440 will start on October 15 (Sunday), 08:05 (UTC). It will be based on Technocup 2018 Elimination Round 2. So, if you are a Russian-speaking high-school student, please take part in the Technocup 2018.

Codeforces Round 440 is open and rated for everyone.

Wish you good luck and bugless code.

Editorial is posted.

Congratulations to winners!

Technocup official round:

1. Mikhniuk
2. scanhex
3. Krisha
4. lis
5. FalseMirror

Div. 1:

1. khadaev
2. Errichto
3. eddy1021
4. FizzyDavid
5. fateice

Div. 2:

1. wdmmsyf
2. Legilimens2023
3. destinydrifter
4. oscar114514
5. OMS

Hello everyone!

From 7 to 16 of November 2017, Moscow International Workshop ACM ICPC 2017 is going to be held at MIPT.

We’d like to remind you that there are only a few days left before the participation cost grows again: if you pay before Oct.16, 2017, the price will be $600.

What’s more, if you have tight curricula, you can choose a short Workshop program which lasts from 9 to 16 of November 2017. Please, pay attention that the prices for a short program are also reduced.

Also you can apply for online participation and solve all the contests remotely.

This time you’ll see some new features:

1)Sometimes the coaches and ACM-ICPC seniors will be present during the upsolving, so you can ask them questions. (Special thanks to the guys who give us feedback about our Workshops!)

2) There will be organized one lecture for the division A, which will be interesting for the strongest participants.

In addition to contests, analyses, and lectures, you’ll enjoy a sightseeing tour in Moscow and events organized by our volunteers! ;)