Привет, Codeforces!

On Dec/18/2022 17:35 (Moscow time), Codeforces Round 839 (Div. 3) will start. This is a usual round for the participants from the third division. The round will contain 7 problems, which are mostly suited for participants with rating below 1600 (or we hope so). Although, as usual, participants with rating of 1600 and greater can register for the round unofficially.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks.

You will be given 7 problems and 2 hours and 15 minutes to solve them. The penalty for a wrong submission is equal to 10 minutes.

We remind you that only the trusted participants of the third division will be included in the official standings table. As it is written on the blog which you can access by this link, this is a compulsory measure for combating unsporting behavior. To qualify as a trusted participant of the third division, you must:

• take part in at least two rated rounds (and solve at least one problem in each of them),
• not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

The problems were invented and prepared by Adilbek adedalic Dalabaev, Ivan BledDest Androsov, Maksim Neon Mescheryakov and me. We would like to thank the testers of the round: ermukanoff, soup, lankin.i, Fanarill, stAngel and senjougaharin. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

UPD: Editorial is out

Hello, Codeforces!

Winter holiday is coming! And we are excited to invite you to our third round, Polynomial Round 2022 (Div. 1 + Div. 2, Rated, Prizes!), which will be held on Dec/17/2022 17:35 (Moscow time). You are given 8 problems and 2.5 hours to solve them.

All problems were written and prepared by Ecrade_, Little09, ChthollyNotaSeniorious, JianfengZhu, Cirno_9baka, mejiamejia and me.

And thanks to dorijanlendvaj, gisp_zjz, gamegame, triple__a, Chenyu_Qiu, Suiseiseki, aaaaawa, leukocyte, waaitg, Kubic, LHQing, RedLycoris, lucaperju, njupt_lyy, Kilo_5723, Huah, prvocislo, foreverlasting, thanhchauns2, Rhodoks, JohnVictor, Psychotic_D, VinstaG173, dannyboy20031204, 4qqqq, CoupDeGrace, wsyear, 5ab, Lavine, absi2011, UtopianZ for testing and good advice, antontrygubO_o for his excellent round coordination and help with preparation and MikeMirzayanov for great systems Codeforces and Polygon.And you, for participating!

This is our third round! Although you may find members in our team and testers who helped are not the same as the past, our permanent love and enthusiasm for coding will not change. Conspicuously, great efforts have been put in it. We are sincerely looking forward to your participation and we hope everyone will enjoy it. Besides, this round is sponsored, which indicates that everyone has an opportunity to get the prize!

UPD1: Here is the score distribution:

500 — 1000 — 1500 — 1500 — 2000 — (1500 + 1000) — 3250 — 4000

UPD2: Sorry to everyone! We must apologize because the pretest of B is not strong, leading to FST for many people. It is our fault! We don't want to make excuses. This time, we did a bad job and let everyone down. We all blamed ourselves sadly. Although we have invited a lot of testers but most of them passed all the tests, and even some of them get 'WA', they fixed their code and passed it. So we didn't pay too much attention to it -- we thought it was 'normal'. However, we didn't suppose the pretests were so weak that lots of participants get FST. Sorry again! (>_<)

And personally, firstly, I must apologize to all of you. I let you down this time. I blamed myself sadly. And I accept all the critical opinions. However, secondly, I know that you must feel angry when you find your B got FST, and that's all our fault, but because my birthday is coming, I intended to use this contest to record the growth of me and my team members, as well as my happy memories on codeforces, so could you please don't scold me too harshly when criticizing me? (Actually I am crying when typing this words; I blamed myself sadly when I saw lots of FST). I will regard all your comments as the most valuable things which urge me to become a better person and help me grow to a more mature person, but maybe I will be very painful if I see comments or messages as 'you are a trash''trash round'. (⑉꒦ິ^꒦ິ⑉)

Sorry! We did a bad job because of our carelessness this time, but we promise we will try our best to improve our comprehensive abilities, and bring a better round next time! We will keep in mind every word of encouragement and criticism, which is the driving force for our growth. Wish you happy everyday! (•ω•)

UPD3: Tutorial is available.

Thanks for all the warmth and kindness!!! I felt deeply guilty during the past few hours, now I feel better. I really appreciate your warmth and kindness!!! (●'◡'●)

We made the contest just because we would like to share our interesting ideas with you. If you like any of the ideas, we will be very delighted!!! o(≥ω≤)o

UPD4:Congratulations to the winners

1. Um_nik
2. maroonrk
3. tourist
4. inaFSTream
5. ksun48
6. LJC00118
7. ugly2333
8. bruhopen
9. ecnerwala
10. Rewinding

And for my personal gifts: the two random number is 91 and 1028, so congratulations to sd0061 and regain0001!!! (The rank contained the virtual participants at that time, which improves randomness, only if the time and the rank both accorded with the number , you can get the gifts!!!) o(〃'▽'〃)o

Thanks to all the warmth and kindness!!! You really light up my heart!!! We will try our best next time and prepare a better round to share our interesting ideas with you!!! ✧⁺(๑•ω•๑)⁺✧

And here is the information from our title sponsor:

Prizes

The participants who end up in the first 255 positions will receive prizes. The participant on the first place will receive $256, the next two participants will receive $128, the next four participants will receive $64, etc. Prizes will be distributed in OP (Optimism) tokens.

About Polynomial

Polynomial is building in decentralized finance – a more fair, accessible, efficient, and transparent financial system enabled by crypto. Polynomial automates financial derivative strategies to create products that deliver passive yield on various assets. Polynomial Earn is the first DeFi Options Vault (DOV) that executes completely on-chain by selling options directly to an AMM.

If you have a background in mathematics or software engineering and a knack for problem-solving, we want to hear from you. You will have the opportunity to work on cutting-edge technology and tackle complex problems alongside a talented and driven team.

By joining us at this early stage, you will make fundamental decisions that will shape the course of Polynomial. We prefer passionate, quick learners with a history of excellence.

Find out more about us on our website polynomial.fi or texting rivalq.

If you wish to be part of our remote-first team or apply for an internship, please fill in the form or email [email protected]. Make sure to apply before Dec 20, 2022.

We wish everyone good luck and have a positive delta!

Hello Codeforces!

On Dec/16/2022 17:35 (Moscow time) Educational Codeforces Round 140 (Rated for Div. 2) 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 round will be rated for the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 6 or 7 problems and 2 hours to solve them.

The problems were invented and prepared by Adilbek adedalic Dalabaev, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov, Alexey shnirelman Shnirelman and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

Our friends at Harbour.Space also have a message for you:

Harbour.Space University has partnered with Noventiq, the leading global solutions and services provider in digital transformation and cybersecurity, to offer motivated Data Scientists the opportunity to work and study in Barcelona. We are looking to distribute scholarships for intensive study programmes at the highest level, for eligible candidates that will be able to join our journey.

Candidates will be working on the following tasks:

• Invent and implement approaches to solving problems of computer vision and machine learning, form requirements together with the team;
• Plan experiments, train models, evaluate their quality and embed them in pipelines;
• Work with data, the formation of technical requirements for markup;
• Register the results of training runs of models and track the dynamics of their performance;
• Write algorithms for pre- and post-processing of images and videos, the logic of scenarios for processing media data;
• Conduct research in the field of Computer Vision: classification, detection, segmentation;
• Engage in the optimization of neural networks: distillation, quantization, pruning;
• Prepare models for production;
• Carry out the development of custom algorithms and modules of our video analytics platform.

All successful applicants will be eligible for a 100% tuition fee scholarship (22.900 €/year) provided by Noventiq company for Data Science.

CANDIDATE’S COMMITMENT

Study Commitment: 3 hours/day ‍

You will complete 15 modules (each three weeks long) in one year. The daily class workload is 3 hours, plus homework to complete in your own time.

Work Commitment: 6 hours/day ‍

Immerse yourself in the professional world during your apprenticeship. You’ll learn from the best and get to apply your newly acquired knowledge in the field from day one.

University requirements

1. Bachelor's degree in the field of Mathematics, Statistics, Data Science, Computer Science or similar
2. English proficiency

Work requirements

• Excellent knowledge and experience in using Python, as well as TensorFlow/PyTorch;
• Experience in implementing Deep Learning models for commercial projects;
• Experience in solving real problems in the field of Computer Vision;
• Experience with Linux OS, Git, Docker;
• Understand the principles of operation of current popular architectures of neural networks;
• Possession of the culture of conducting experiments, you know about reproducibility and logging, you can objectively assess the quality of the model;
• Spanish language proficiency;

Good luck,

Harbour.Space University Team

UPD: Editorial is out

Hello, Codeforces!

amurto and I are glad to invite everyone to participate in Codeforces Round 838 (Div. 2), which will be held on Dec/15/2022 17:35 (Moscow time).

This Round will be rated for participants with rating strictly lower than 2100. Participants from the first division are also welcomed to take part in the competition but it will be unrated for them.

You will be given 7 problems and 2 hours and 30 minutes to solve them. One of the problems will be interactive. Make sure to read this blog and familiarize yourself with these types of problems before the round!

We would like to thank:

• errorgorn for amazing coordination and help with the problem preparation.
• KAN for translation of the statements into Russian
• TheScrasse for providing suggestions which helped us to improve one problem.
• GoatTamer for discussing problems with us while our proposal was in review and testing the round.
• dorijanlendvaj, Um_nik, tabr, jeroenodb, Kira_1234, rivalq, thenymphsofdelphi, MagentaCobra, prvocislo, towrist, maomao90, IceKnight1093, AGRU, Omja, valeriu, TheScrasse, Perpetually_Purple, priyanshu_bhardwaj, Nahian9696, koderkushy, Non-origination, brobat, jampm, nyaruhodo, the_hyp0cr1t3, iLLusio, Utkarsh.25dec, ak2006, AlperenT, physics0523, udhavvarma03, welleyth, meme, SlavicG, MasterRayuga, recurecurring, dedsec_29, blitztage, Mo2men and tibinyte for testing this round and providing feedback.
• MikeMirzayanov for great Codeforces and Polygon platforms.

Score distribution is 500 — 1000 — 1750 — 2000 — 2500 — 2750 — 3500.

UPD1: Congratulations to the winners!

Overall:

• jiangly
• antontrygubO_o
• Hyperbolic
• tute7627
• A_G

Rated:

• _gxyd
• NoPotato
• Alphaqwq_
• MironRaisa
• Hanasaki

UPD2: Editorial is out.

We are looking forward to your participation!

Hello Codeforces!

On Dec/12/2022 17:35 (Moscow time) Educational Codeforces Round 139 (Rated for Div. 2) 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 round will be rated for the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

You will be given 6 or 7 problems and 2 hours to solve them.

The problems were invented and prepared by Adilbek adedalic Dalabaev, Vladimir vovuh Petrov, Ivan BledDest Androsov, Maksim Neon Mescheryakov and me. Also huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Good luck to all the participants!

UPD: Editorial is out

Hello, Codeforces!

I am glad to invite everyone to participate in Codeforces Round #837 (Div. 2) , which will be held on 11.12.2022 18:35 (Московское время)

Please note the unusual time!

The round will be rated for participants of Division 2 with a rating lower than 2100. Division 1 participants can participate unofficially in the round.

You will be given 6 problems and 2 hours to solve them. This round was prepared by me and 4qqqq.

I'd especially like to thank:

• Aleks5d for awesome coordination of our round.
• MikeMirzayanov, for the amazing Codeforces and Polygon platforms.
• ashmelev, TurboPiKachu, divanik, olya.masaeva, nnv-nick, neohacker, PavelKorchagin and Kolychestiy for testing the round and providing valuable feedback.

This is my first official round on Codeforces. We are sincerely looking forward to your participation. We hope everyone will enjoy it.

The score distribution : 500 — 1000 — 1750 — 2250 — 2750 — 3500

We wish you good luck and high rating!

UPD1: We know about problem with C task. Now we are trying to fix it.

Editorial.

Hello!

Tomorrow (December 7th) the ICPC Northern Eurasia Finals (previously known as NEERC) will take place. The competition will be held at several venues: St. Petersburg, Barnaul, Kutaisi and Almaty. Almost 300 teams will take part in it.

We invite you to join the online mirror of the competition: 2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred). It will start at Dec/07/2022 11:05 (Moscow time). We recommend participating in teams, but experienced individual participants will also have fun.

The duration of the competition will be 5 hours. Of course, the round is unrated.

Good luck!

Hello, Codeforces!

Great news! Here's another opportunity to take a part in an exciting event from our main sponsor.

The contest for smart contract developers with a total prize fund of 50,000 TON begins on 2 Dec. 12:00 UTC and lasts until 23 Dec. 18:00 UTC. TON Smart Challenge #3 will be suitable for experienced developers as well as for beginners that are ready to dive into FunC.

TON Smart Challenge #3 tasks will be dedicated to the basic aspects of how smart contracts work in TON: complex manipulations with cells, organizing the storage of smart contracts, working with comments, basic cryptography and the logic of governance smart contracts.

A contest aimed at optimization of 5 smart contracts written in the FunC language native for The Open Network blockchain. The goal of the contest is to optimize contract execution cost, preserving functionality and business logic. One may find more information about development in TON here.

Register through the @toncontests_bot to be notified, when it starts, and stay up to date