awoo's blog

By awoo, history, 12 days ago, translation, In English

2026A - Perpendicular Segments

Idea: adedalic

Tutorial
Solution (adedalic)

2026B - Black Cells

Idea: BledDest

Tutorial
Solution (Neon)

2026C - Action Figures

Idea: BledDest

Tutorial
Solution (BledDest)

2026D - Sums of Segments

Idea: shnirelman

Tutorial
Solution (BledDest)

2026E - Best Subsequence

Idea: BledDest

Tutorial
Solution (Neon)

2026F - Bermart Ice Cream

Idea: BledDest

Tutorial
Solution (awoo)

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By awoo, history, 2 weeks ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos. They offer a BSc in Computer Science and AI with JetBrains Scholarships. Gain cutting-edge skills in AI and machine learning, preparing you for high-demand tech careers. Curious? Join the livestream on Tuesday, October 29 at 5:00 pm UTC to learn about the CSAI program’s curriculum, course structure, scholarships, student internships, and their hands-on learning approach.

Want more experience in coding and math competitions?
JetBrains Youth Challenge returns in November 2024!

Who can join?
Ages 13–18
Anyone currently enrolled in secondary education
Register now

On Oct/28/2024 17:35 (Moscow time) Educational Codeforces Round 171 (Rated for Div. 2) will start.

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 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

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By awoo, history, 4 weeks ago, translation, In English

2025A - Two Screens

Idea: BledDest

Tutorial
Solution (BledDest)

2025B - Binomial Coefficients, Kind Of

Idea: adedalic

Tutorial
Solution (adedalic)

2025C - New Game

Idea: fcspartakm

Tutorial
Solution (awoo)

2025D - Attribute Checks

Idea: adedalic

Tutorial
Solution 1 (adedalic)
Solution 2 (adedalic)

2025E - Card Game

Idea: BledDest

Tutorial
Solution (Neon)

2025F - Choose Your Queries

Idea: BledDest

Tutorial
Solution (BledDest)

2025G - Variable Damage

Idea: BledDest

Tutorial
Solution (awoo)

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By awoo, history, 4 weeks ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos. They offer a BSc in Computer Science and AI with JetBrains Scholarships. Gain cutting-edge skills in AI and machine learning, preparing you for high-demand tech careers. Curious? Check out the CSAI curriculum now. Limited scholarships available — don't miss your chance to study in Europe for free!

Are you looking to sharpen your skills and increase your chances of getting a scholarship? Join the free clubs for high school students from JetBrains:

On Oct/14/2024 17:35 (Moscow time) Educational Codeforces Round 170 (Rated for Div. 2) will start.

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, Aleksandr fcspartakm Frolov 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 Qualification stage of the Southern and Volga Russian Regional Contest. If you took part in the qualification, please refrain from participating in the round.

Good luck to all the participants!

UPD: Editorial is out

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By awoo, history, 3 months ago, translation, In English

2004A - Closest Point

Idea: BledDest

Tutorial
Solution (BledDest)

2004B - Game with Doors

Idea: BledDest

Tutorial
Solution (Neon)

2004C - Splitting Items

Idea: BledDest

Tutorial
Solution (adedalic)

2004D - Colored Portals

Idea: BledDest

Tutorial
Solution (Neon)

2004E - Not a Nim Problem

Idea: BledDest

Tutorial
Solution (BledDest)

2004F - Make a Palindrome

Idea: BledDest

Tutorial
Solution (Neon)

2004G - Substring Compression

Idea: BledDest

Tutorial
Solution (awoo)

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By awoo, history, 3 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos. They offer a BSc in Computer Science and AI with JetBrains Scholarships. Gain cutting-edge skills in AI and machine learning, preparing you for high-demand tech careers. Curious? Check out the CSAI curriculum now. Limited scholarships available — don't miss your chance to study in Europe for free!

On Aug/15/2024 17:35 (Moscow time) Educational Codeforces Round 169 (Rated for Div. 2) will start.

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 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

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By awoo, history, 3 months ago, translation, In English

1997A - Strong Password

Idea: BledDest

Tutorial
Solution (BledDest)

1997B - Make Three Regions

Idea: BledDest

Tutorial
Solution (Neon)

1997C - Even Positions

Idea: BledDest

Tutorial
Solution (adedalic)

1997D - Maximize the Root

Idea: BledDest

Tutorial
Solution (Neon)

1997E - Level Up

Idea: BledDest

Tutorial
Solution 1 (awoo)
Solution 2 (awoo)

1997F - Chips on a Line

Idea: BledDest

Tutorial
Solution (BledDest)

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By awoo, history, 3 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Jul/30/2024 17:35 (Moscow time) Educational Codeforces Round 168 (Rated for Div. 2) will start.

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 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

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By awoo, history, 4 months ago, translation, In English

1989A - Catch the Coin

Idea: BledDest

Tutorial
Solution (awoo)

1989B - Substring and Subsequence

Idea: BledDest

Tutorial
Solution (Neon)

1989C - Two Movies

Idea: BledDest

Tutorial
Solution (Neon)

1989D - Smithing Skill

Idea: BledDest

Tutorial
Solution (adedalic)

1989E - Distance to Different

Idea: BledDest

Tutorial
Solution (BledDest)

1989F - Simultaneous Coloring

Idea: BledDest

Tutorial
Solution (awoo)

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By awoo, history, 5 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Jun/27/2024 17:35 (Moscow time) Educational Codeforces Round 167 (Rated for Div. 2) will start.

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, Roman Roms Glazov 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

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By awoo, history, 5 months ago, translation, In English

1976A - Verify Password

Idea: BledDest

Tutorial
Solution (awoo)

1976B - Increase/Decrease/Copy

Idea: BledDest

Tutorial
Solution (Neon)

1976C - Job Interview

Idea: BledDest

Tutorial
Solution (BledDest)

1976D - Invertible Bracket Sequences

Idea: BledDest

Tutorial
Solution (Neon)

1976E - Splittable Permutations

Idea: BledDest

Tutorial
Solution (BledDest)

1976F - Remove Bridges

Idea: BledDest

Tutorial
Solution (awoo)

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By awoo, history, 5 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On May/30/2024 17:35 (Moscow time) Educational Codeforces Round 166 (Rated for Div. 2) will start.

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, Roman Roms Glazov 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

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By awoo, history, 6 months ago, translation, In English

1969A - Two Friends

Idea: BledDest

Tutorial
Solution (awoo)

1969B - Shifts and Sorting

Idea: BledDest

Tutorial
Solution (adedalic)

1969C - Minimizing the Sum

Idea: BledDest

Tutorial
Solution (Neon)

1969D - Shop Game

Idea: BledDest

Tutorial
Solution (Neon)

1969E - Unique Array

Idea: BledDest

Tutorial
Solution (Neon)

1969F - Card Pairing

Idea: BledDest

Tutorial
Solution (BledDest)

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By awoo, history, 6 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Apr/29/2024 17:35 (Moscow time) Educational Codeforces Round 165 (Rated for Div. 2) will start.

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, Roman Roms Glazov 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

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By awoo, history, 7 months ago, translation, In English

1954A - Painting the Ribbon

Idea: BledDest

Tutorial
Solution (BledDest)

1954B - Make It Ugly

Idea: BledDest

Tutorial
Solution (awoo)

1954C - Long Multiplication

Idea: BledDest

Tutorial
Solution (Neon)

1954D - Colored Balls

Idea: BledDest

Tutorial
Solution (Neon)

1954E - Chain Reaction

Idea: BledDest

Tutorial
Solution 1 (awoo)
Solution 2 (awoo)

1954F - Unique Strings

Idea: adedalic

Tutorial
Solution (adedalic)

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By awoo, history, 7 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Neapolis University Pafos.

On Apr/12/2024 17:35 (Moscow time) Educational Codeforces Round 164 (Rated for Div. 2) will start.

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, Roman Roms Glazov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big thanks to the tester shnirelman for his valuable advice and suggestions!

Good luck to all the participants!

UPD: Editorial is out

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By awoo, history, 8 months ago, translation, In English

1948A - Special Characters

Idea: BledDest

Tutorial
Solution (Neon)

1948B - Array Fix

Idea: BledDest

Tutorial
Solution (Neon)

1948C - Arrow Path

Idea: BledDest

Tutorial
Solution (Neon)

1948D - Tandem Repeats?

Idea: BledDest

Tutorial
Solution (awoo)

1948E - Clique Partition

Idea: BledDest

Tutorial
Solution (BledDest)

1948F - Rare Coins

Idea: BledDest

Tutorial
Solution (Neon)

1948G - MST with Matching

Idea: BledDest

Tutorial
Solution (BledDest)

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By awoo, history, 8 months ago, translation, In English

Neapolis University Pafos

Hello Codeforces!

We are pleased to announce a new long-term partnership between Codeforces and Neapolis University Pafos. Now educational rounds will be supported by Neapolis University Pafos. Stay tuned and you will find out more soon.

On Mar/15/2024 17:35 (Moscow time) Educational Codeforces Round 163 (Rated for Div. 2) will start.

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, Roman Roms Glazov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big thanks to the testers shnirelman and Optoed for their valuable advice and suggestions! Special thanks to Vladosiya for his help with the round.

Good luck to all the participants!

UPD: Unfortunately, there were issues with the problem E judgement during the contest. There were only 18 participants affected by it, so the round stays rated. Rated participants whose verdict on problem E changed may request unrated participation (they have received the directions on how to change their participation to unrated). If you have not received any personal notifications about it in the contest dashboard, you have not been affected.

UPD2: Editorial is out

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By awoo, history, 9 months ago, translation, In English

1923A - Moving Chips

Idea: BledDest

Tutorial
Solution (BledDest)

1923B - Monsters Attack!

Idea: BledDest

Tutorial
Solution (Neon)

1923C - Find B

Idea: Roms

Tutorial
Solution (Roms)

1923D - Slimes

Idea: BledDest

Tutorial
Solution (Neon)

1923E - Count Paths

Idea: BledDest

Tutorial
Solution (awoo)

1923F - Shrink-Reverse

Idea: adedalic

Tutorial
Solution (adedalic)

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By awoo, history, 9 months ago, translation, In English

Hello Codeforces!

On Feb/23/2024 17:35 (Moscow time) Educational Codeforces Round 162 (Rated for Div. 2) will start.

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, Roman Roms Glazov 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

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By awoo, history, 10 months ago, translation, In English

1922A - Tricky Template

Idea: Roms

Tutorial
Solution (awoo)

1922B - Forming Triangles

Idea: Roms

Tutorial
Solution (Roms)

1922C - Closest Cities

Idea: BledDest

Tutorial
Solution (Roms)

1922D - Berserk Monsters

Idea: BledDest

Tutorial
Solution (Neon)

1922E - Increasing Subsequences

Idea: Roms

Tutorial
Solution (Neon)

1922F - Replace on Segment

Idea: Roms

Tutorial
Solution (Neon)

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By awoo, history, 10 months ago, translation, In English

Hello Codeforces!

On Jan/18/2024 17:35 (Moscow time) Educational Codeforces Round 161 (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, Roman Roms Glazov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big thanks to the testers shnirelman and Minder for their valuable advice and suggestions!

Good luck to all the participants!

UPD: Editorial is out

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By awoo, history, 11 months ago, translation, In English

1914A - Problemsolving Log

Idea: BledDest

Tutorial
Solution (awoo)

1914B - Preparing for the Contest

Idea: Roms

Tutorial
Solution (BledDest)

1914C - Quests

Idea: Roms

Tutorial
Solution (Neon)

1914D - Three Activities

Idea: BledDest

Tutorial
Solution (awoo)

1914E1 - Game with Marbles (Easy Version)

1914E2 - Game with Marbles (Hard Version)

Idea: BledDest

Tutorial
Solution (adedalic)

1914F - Programming Competition

Idea: BledDest

Tutorial
Solution (Neon)

1914G1 - Light Bulbs (Easy Version)

1914G2 - Light Bulbs (Hard Version)

Idea: BledDest

Tutorial
Solution (BledDest)

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By awoo, history, 11 months ago, translation, In English

Hello, Codeforces!

On Dec/19/2023 17:35 (Moscow time) the Codeforces Round 916 (Div. 3) will start. You will be offered 6-8 problems with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have a rating of 1600 or higher, 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 2 hours and 15 minutes to solve 6-8 problems. 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 five 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, Roman Roms Glazov, Alexander fcspartakm Frolov, and me. Also, big thanks to Vladislav Vladosiya Vlasov for his excellent coordination.

Thanks to Mike MikeMirzayanov Mirzayanov for Codeforces and Polygon systems!

And, the last but not the least, big thanks to the testers FBI, Kalashnikov and SonOfHonor for their valuable advice and suggestions!

Good luck in the contest! I hope you'll enjoy solving the problems we have prepared.

UPD: Editorial is out

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By awoo, history, 11 months ago, translation, In English

1902A - Binary Imbalance

Idea: BledDest

Tutorial
Solution (awoo)

1902B - Getting Points

Idea: adedalic

Tutorial
Solution (adedalic)

1902C - Insert and Equalize

Idea: Roms и BledDest

Tutorial
Solution (awoo)

1902D - Robot Queries

Idea: BledDest

Tutorial
Solution (Neon)

1902E - Collapsing Strings

Idea: Roms

Tutorial
Solution (Roms)

1902F - Trees and XOR Queries Again

Idea: BledDest

Tutorial
Solution (BledDest)

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