Hello, Codeforces! ☀️☀️☀️

We are glad to invite you to our second Div. 3 round, which will take place on Nov/17/2023 17:35 (Moscow time). The round will be rated for all participants with rating less than 1600.

You will be given 7 tasks and 2 hours 15 minutes to solve it.

The tasks were prepared by zwezdinv, meowcneil, EJIC_B_KEDAX, Sokol080808 and molney.

Remember, that only trusted Div. 3 participants will be included in official standings. To qualify as trusted participant you need:

1. Participate in at least five rounds (and solve at least one problem in each of them)
2. Do not to have a point 1900 or greater in the rating

We would like to thank:

• MikeMirzayanov for Polygon and Codeforces
• Coordinators Vladosiya and Gornak40 for excellent coordination
• ace5, pavlekn, 998kover, EternalAlexander, Rubikun for red testing
• Kihihihi, Be_dos, alex.kudryashov, makrav, exhausted, 74TrAkToR, turkhuu622, _LeMur_, beemax, sedev57, misorin for yellow testing
• azureglow, Alex239, SashaT9, Pa_sha, goncharovmike for purple testing
• zarubin, OR_LOVe, TimVen74, ivan.alexeev, krigare, marzipan, Algolagon, Apachee, EzikBro, null0124, KoT_OsKaR, micho, keroru, dasha..zhilina for blue testing
• ilqw, El_Gemmy for cyan testing
• Flash700 for gray testing

Good luck everyone!

UPD: Editorial

Big greetings, Codeforces!

I am happy to invite you to Codeforces Round 908 (Div. 1), Codeforces Round 908 (Div. 2), which will be held on Nov/07/2023 17:35 (Moscow time).

This round will be rated for everyone. In both divisions, you will be given 5 problems and 120 minutes to solve them. All problems were cooked by me (sevlll777).

The traditional thanks-list to everyone who took part in the creation of the round. Thanks,

• 74TrAkToR for incredible coordination!

• gzchenben, Gary2005, SomethingNew, Sugar_fan, FairyWinx, EternalAlexander, RUSH_D_CAT, rsj, Kieray, CtrlAlt, Vladithur, nnv-nick, AndZhi, p_b_p_b, Adam_GS, tem_shett, 127.0.0.1, a.nasretdinov, Suiseiseki, Aokana, noimi, Psychotic_D for testing the round.

• CtrlAlt for help with polishing the statements.

• MikeMirzayanov for Polygon and Codeforces platforms.

I hope you will like the problemset and ideas hidden in the problems! It's guaranteed that statements are understandable, short, and, of course, ✨ stylish ✨.

Have fun!

Score Distribution:

Div. 1: $$$500$$$ — $$$1000$$$ — $$$1250$$$ — $$$2250$$$ — $$$2750$$$

Div. 2: $$$500$$$ — $$$750$$$ — $$$1500$$$ — $$$2000$$$ — $$$2250$$$

UPD: Editorial

UPD2: Congrats to the chAAAmpions!

Div.1:

1. maroonrk

2. Ormlis

3. Um_nik

4. tourist

5. 5sb

6. Swistakk

7. jiangly

8. Radewoosh

9. ethening

10. hank55663

Div.2:

1. Redpo

2. shenzihan

3. lq5

4. zookeeper780

5. omsincoconut

6. vishav_mehra

7. menezesd2

8. darling51707

9. kanao_enjoyer

10. bleeding

Hello Codeforces!

On Nov/03/2023 17:35 (Moscow time) Educational Codeforces Round 157 (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, Ivan BledDest Androsov, Maksim Neon Mescheryakov, Artem Ferume Ilikaev, Ruslan AcidWrongGod Kapralov, Alexey ashmelev Shmelev, Alex fcspartakm Frolov, Dmitry DmitryKlenov Klenov, Dmitry dmitryme Mescheryakov, Elena elena Rogacheva and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Please note that the problems of this round partially intersect with the problems of the Southern and Volga Russian Regional Contest. If you took part in that contest, please refrain from participating in the round.

Good luck to all the participants!

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

BIMBA Y LOLA has partnered with Harbour.Space University to offer a Master's Degree scholarship in Computer Science, as well as work experience as a Junior Java Developer at the Development Team in BIMBA y LOLA.

At BIMBA Y LOLA, they understand the importance of counting on the most creative professionals, those with an enterprising spirit and passion for their work. They are seduced by talent, sensibility, initiative, an analytical nature, commitment to quality, a keen eye and a love for detail. And, of course, a clear vocation for fashion.

If you share these values, we are offering a young, dynamic and stimulating environment; one in which to progress and develop professionally; a company present in over 18 countries and embarked on an ambitious international expansion plan.

All successful applicants will be eligible for a 100% Tuition Fee Scholarship (29,900€/year) provided by BIMBA Y LOLA.

Requirements:

• Spanish and English language proficiency is a MUST
• Bachelor's degree in the field of Mathematics, Statistics, Data Science, Computer Science or similar

The candidate should be familiar with:

• Agile Methodologies (scrum)
• GIT
• Java 8/11+
• Spring
• Maven
• JUnit
• Mockito
• UML
• HTML
• CSS
• Javascript
• ReactJS
• SQL Server/MySQL

Desirable skills:

• Azure
• Azure DevOps — Pipelines
• Docker
• Kubernetes
• Helm
• Jira
• Confluence

Apprenticeship Summary:

• 100% Tuition Fee Scholarship to study a Master’s Degree in Computer Science for one year.
• 4 hours/day internship on campus.
• Competitive compensation.
• Opportunity to join the company full-time after graduation.
• Please note that preselected candidates will be requested to pay a non-refundable Application Fee of 125€ for assessment.

Candidate’s commitment:

• Study Commitment: 4 hours/day
• ‍You will complete 15 modules (each three weeks long) in one year.
• Daily class workload is 3 hours, plus homework to complete in your own time.
• Work Commitment: 4+ 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.

UPD: Editorial is out

Hello, Codeforces!

max0000561, a.nasretdinov and I are glad to invite you to our Codeforces Round 907 (Div. 2), which will be held on Oct/30/2023 17:35 (Moscow time). The round will be rated for all the participants with rating strictly less than 2100.

On behalf of our team, I want to thank:

• Coordinator 74TrAkToR for invaluable help in preparing the round.
• Testers maomao90, LeoPro, SomethingNew, maks_matiupatenko, max0000561, yaroslav_n, glebustim, Vash_nick, Murinh0, Topperoo, Alarick, priyanshu.p, Greg908, buffering, ventilator13, medved, zwezdinv, Rodionno for high-quality testing of the round and useful feedbacks!
• medved for excellent translations of the problems into English.
• MikeMirzayanov for amazing Codeforces and Polygon platforms.

And special thanks to my friends who have made a huge contribution to this round: Amir a.nasretdinov Nasretdinov, Maksim max0000561 Krylykov and Tanya medved Medved. Also thank you for all four years of friendship:)

During the round you will need to solve 6 problems. You will have 2 hours to solve them.

Score distribution: $$$500-750-1000-1500-2000-2250$$$

Good luck and, please, read the statements of all problems!

UPD: Editorial is out.

UPD 2: Congratulations to the winners!

Div. 1:

• neal
• arvindf232
• kotatsugame
• maspy
• Geothermal

Div. 2:

• ETO
• MikeMirzayakahashi
• stklight
• win1919810
• Little_Leaf

Hello, Codeforces!

waaitg, Cocoly1990 and I are glad to invite you to Codeforces Round 906 (Div. 1) and Codeforces Round 906 (Div. 2), which will take place on Oct/28/2023 17:35 (Moscow time). In both divisions, you will be given 6 problems and 2 hours and 30 minutes to solve them all. Note that one of the tasks is split into two subtasks.

We would like to thank:

• TheScrasse for his brand new coordination.
• KAN for the great help with round preparation.
• Alexdat2000 for Russian translation.
• errorgorn for his 1-year coordination and Monogon for his 2-year coordination of one problem.
• waaitg for donating his Dead by Daylight time to prepare the problems.
• errorgorn, Kubic, zhangjianjuncd, doroc, DoverHi, alwyn, Yakumo_Ran, AquaMoon, Vladithur, DrSwad, abc864197532, null_awe, irkstepanov, KAN, gamegame, tnaito, _irohasu_, uwu, Xylenox, Anonymous_Noob, GusFring, LRJf, SomethingNew, avi15 and gs20036 for testing the round and their invaluable feedbacks.
• Vladithur, errorgorn for their profound contribution in tests making.
• MikeMirzayanov for amazing platform Codeforces and Polygon.

Score distribution:

Div. 2: $$$500$$$ — $$$750$$$ — $$$1250$$$ — $$$2000$$$ — $$$(1250 + 2500)$$$ — $$$3250$$$
Div. 1: $$$750$$$ — $$$1250$$$ — $$$(750 + 1500)$$$ — $$$2000$$$ — $$$3500$$$ — $$$3500$$$

As always, wish you all get a non-negative delta in this round!

UPD1: Editorial

UPD2: congratulations to the winners!

Hello, Codeforces!

We are happy to invite you to our experimental round for three divisions, which will take place at Oct/22/2023 14:05 (Moscow time). Please note the non-standard start time for the round. Each division will have 5-7 tasks. The round will be held according to the Codeforces rules and will be rated for all three divisions. A few changes regarding the ratings of participants in this competition:

• In Div.3 the rating of participants is less than 1600.
• In the Div.2 ranking, participants range from 1600 to 2099.
• In Div.1 the rating of participants is no less than 2100.
• Please note that after Codeforces Round 904 (Div. 2) the rating will not be recalculated until the end of this competition.

Let us note that two team Olympiads will be held in parallel on this day and the rounds are based on their tasks:

• XXI Moscow Team Olympiad, high school students competition based in Moscow that is an elimination contest for All-Russian Team Olympiad.
• III Open Team Olympiad UMSh in programming.

We would like to thank everyone who helped me a lot with round preparation.

• Coordinators Artyom123 и Vladosiya for excellent coordination and useful advice.
• Problem authors 74TrAkToR, Mangooste, TheEvilBird, Tikhon228, teraqqq, valerikk, Dmitry07.
• Testers pavlekn, zwezdinv, plagues, SashaT9, Maks_Simenkov, orolik, tmari_sun, OR_LOVe, _why_not_, TimVen74, zarubin, myav, ctraxxd, Gassa, OAleksa, Acanikolic73, AndrewPav, AlphaMale06, NemanjaSo2005, dorijanlendvaj, defnotmee, meOwO, Umi, CIXTEEN, golions, MagentaCobra, FairyWinx, v0s7er, adepteXiao, induk_v_tsiane, Alexdat2000, Be_dos, mr.kolya, kevinxiehk, alexxela12345, talant, daubi for high-quality testing!
• MikeMirzayanov for amazing Codeforces and Polygon platforms.

We wish you good luck and high rating!

UPD: One of the problems will be interactive, so please read guide for interactive problems before the contest.

UPD: Score distribution:

• Div.3: $$$500-1000-1500-1750-2500-2750-(1750+2000)$$$
• Div.2: $$$250-500-1000-(750+1250)-2250-2750$$$
• Div.1: $$$(250+500)-750-1000-1250-2000-2750$$$

UPD: Editorial

UPD: We will retest the solutions to the problem div3F and div2C. This may make minor changes, the rating will be recalculated later.

UPD: Retesting took several minutes. Now all the results are correct :)

Hello, Codeforces!

I am happy to invite you to my Codeforces Round 904 (Div. 2) which will be held at Oct/22/2023 10:05 (Moscow time). The round will be rated for all the participants with rating strictly less than 2100.

The tasks were created and prepared by 74TrAkToR. I would like to thank everyone who helped me a lot with round preparation.

• Coordinator irkstepanov for excellent communication and help with preparation.
• Testers Golovanov399, tibinyte, Silver_Fox, azureglow, eeeDA, coder8080, valeriu, XaRDKoDblCH, cristi_tanase, pshat, Vladosiya, DIvanCode, nnv-nick, priyanshu.p for high-quality testing and valuable advices.
• AlFlen for the idea of one of the tasks and two wonderful years together!
• All members of the jury of the team Olympiad CheReKoSH, because the round is made up of the tasks of this Olympiad.
• MikeMirzayanov for amazing Codeforces and Polygon platforms

During the round you will need to solve 5 problems. You will have 2 hours to solve them.

Score distribution: $$$500-1000-1750-2500-3000$$$

We wish you good luck and high rating!

UPD: Editorial

Hello, Codeforces. Friends.

I apologize, but today I will be a bit chaotic and mix personal with public. It just happened that way, I'm sorry.

Today, my mother passed away. It's hard for me to write this. Even just seeing it in text makes it feel like something from a nightmare.

She was extraordinary. It's difficult for me to articulate it right now, but take my word for it. It felt like all the best qualities one could imagine in a mother converged in her. I don't know any other people so kind, sincere, non-judgmental, capable of love, listening, befriending, supporting, and taking joy in the world around them, and bringing joy to their loved ones. Mom, it's already hard without you, it feels empty.

She had glioblastoma. It's an aggressive brain cancer that affects only a few people out of 100,000. I believe, I hope, that science will soon be able to tackle this disease. But for now, this diagnosis is a death sentence. Maybe some of you are or will be associated with medicine. I want to say thank you, I hug you.

Perhaps this is some form of catharsis, but visiting the Codeforces pages today, I pondered why I do this. What am I seeking here?

I want to enter another world. A world free from the insoluble problems of human ambition. A world where we discuss problems, algorithms, and programming.

The world is unjust and restless. It has black, white, blood-red, and some gray shades of unclear tones. But here, on Codeforces, I'm not looking for answers to all questions. I hug all of you and wish you peace, tranquility, and joy.

You may perceive this as a whim of mine, but now I don't want to see topics here that are considerably broader than programming, mathematics, and life outside our competitions. I want a united community, an intellectual oasis.

Focus on our competitions, not on global issues, will help me personally continue to be engaged in the community, develop and move it forward.

Please refrain from making posts, comments, or any other forms of expression on contentious topics like national/ethnic conflicts, politics, religion, sexual orientation, and gender identity, and any other topics distant from programming competitions that might lead to disputes or conflicts. We won't solve these problems here, we just can't.

Give me some time, and I will likely hide the most contentious posts on these topics. Please refrain from publishing anything that is beyond or close to the boundary mentioned above. By publishing materials that contain signs of such discussions, be prepared for read-only mode and other administrative measures.

I realize that I'm now limiting Codeforces and diminishing the community's involvement in our lives. But this is how I feel today, and I ask for your understanding. I wish you peace and love.

M.

P.S. Please cherish your loved ones while they are with you. Give them your attention. Bring joy to them, love them.

UPD 1: Friends, thank you very much for your attention. I read all the comments and am grateful to everyone who supported me.

UPD 2: Yesterday the funeral took place. Thank you for your support. With your help, it's easier for me to get through all of this.

Hello, Codeforces!

I, ChurakovaAlexandra, and medvezhonokok are students of ITMO, and since this August, we started our internship at Codeforces. We are delighted that now we have the opportunity not only to write academic code but to do something that competitive programming enthusiasts from all over the world use.

Currently, we are working on minor improvements to Polygon — a system for preparing problems. Later, as we gain more experience and delve into the technologies, we will also start working on Codeforces.

A big thank you to our mentors geranazavr555 and MikeMirzayanov, who are always there to help and support.

Here's a list of the main improvements to Polygon that we've made (sometimes with significant help from our mentors) over these two months.