awoo's blog

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

Hello Codeforces!

On Jan/29/2020 17:35 (Moscow time) Educational Codeforces Round 81 (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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hello Muscat

Hi Codeforces!

As a special prize for the Educational Round 81, we would like to invite the top participants to take part in our Hello Muscat ICPC Programming Bootcamp, which will take place in Oman, from March 19 to March 25, 2020. The prize will cover the participation fee, accommodation, and half-board meals for the entire duration of the bootcamp (except flights)!

There are three requirements to satisfy:

  • You took part in at least 10 rated contests on Codeforces
  • Your max rating should be less than 2400
  • You should be eligible for ICPC and/or IOI 2020+
Fill out the form→

Good luck to everyone!

We are also excited to announce that we are working with our partners to provide free participation (flights not included) for the teams going to the ICPC World Finals 2020, which will take place in Moscow. If you and your team qualified for the Finals, fill out the form below to see if you’re eligible.

Apply Now→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 nickluo 6 177
2 KrK 6 184
3 NoLongerRed 6 185
4 Anadi 6 200
5 neal 6 204

Congratulations to the best hackers:

Rank Competitor Hack Count
1 GiantTornado 58
2 rachit_raj 51:-1
3 harshraj22 41:-5
4 Ahmad__ 35:-1
5 Sadik 33:-2
1096 successful hacks and 873 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A antontrygubO_o 0:01
B neal 0:05
C IgorI 0:07
D NoLongerRed 0:06
E Egg_Tart_Forest 0:14
F Combi 0:23

UPD: Editorial is out

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

1288A - Deadline

Idea: adedalic

Tutorial
Solution (adedalic)

1288B - Yet Another Meme Problem

Idea: Roms

Tutorial
Solution (Roms)

1288C - Two Arrays

Idea: BledDest

Tutorial
Solution (Roms)

1288D - Minimax Problem

Idea: BledDest

Tutorial
Solution (BledDest)

1288E - Messenger Simulator

Idea: Neon

Tutorial
Solution 1 (pikmike)
Solution 2 (pikmike)
Solution 3 (pikmike)

1288F - Red-Blue Graph

Idea: BledDest

Tutorial
Solution (BledDest)

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

Hello Codeforces!

On Jan/14/2020 17:35 (Moscow time) Educational Codeforces Round 80 (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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hello Muscat

Hi Codeforces!

As a special prize for the Educational Round 80, we would like to invite the top 3 participants to take part in our Hello Muscat ICPC Programming Bootcamp, which will take place in Oman, from March 19 to March 25, 2020. The prize will cover the participation fee, accommodation, and half-board meals for the entire duration of the bootcamp (except flights)!

There are three requirements to satisfy:

  • You took part in at least 10 rated contests on Codeforces
  • Your max rating should be less than 2400
  • You should be eligible for ICPC and/or IOI 2020+
Fill out the form→

Good luck to everyone!

Note: If you really want to participate, but cannot afford the participation fee, get in touch with us to request a supporting letter for you to show to your university, employer, or local companies. With this letter, you are opening the possibility of being sponsored by them to attend the bootcamp.

Please fill out this form and we’ll send you the support letter within 3 days!

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 isaf27 6 150
2 FSTForces 6 167
3 jiangly 6 178
4 ko_osaga 6 179
5 jhnan917 6 184

Congratulations to the best hackers:

Rank Competitor Hack Count
1 surung9898 59:-2
2 stdmultiset 35:-1
3 B2ej5SjC 30
4 spectre_1502 21:-1
5 Dilemma27 20:-4
434 successful hacks and 746 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A okwedook 0:01
B neal 0:04
C ko_osaga 0:06
D RUSH_D_CAT 0:07
E peach 0:17
F jiangly 1:13

UPD: The editorial is out

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

1279A - New Year Garland

Idea: BledDest

Tutorial
Solution (Roms)

1279B - Verse For Santa

Idea: Roms

Tutorial
Solution (Roms)

1279C - Stack of Presents

Idea: Roms

Tutorial
Solution (Roms)

1279D - Santa's Bot

Idea: BledDest

Tutorial
Solution (Ne0n25)

1279E - New Year Permutations

Idea: Neon

Tutorial
Solution (Ne0n25)

1279F - New Year and Handle Change

Idea: vovuh

Tutorial
Solution (vovuh)

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

Hello Codeforces!

On 27.12.2019 17:40 (Московское время) Educational Codeforces Round 79 (рейтинговый для Див. 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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hi Codeforces!

Last spots available for Mike Mirzayanov's course Advanced Algorithms and Data Structures, which will take place in Barcelona, from the 6th to 24th of January, 2020.

The course will consist of three weeks of training, 5 training days each week. The program includes daily lectures and practical exercises. It will be quite educational, insightful and entertaining!

Remember, there’s a special price of 1,000 EUR* for all Codeforces users.

* The cost does not include travel or accommodation.

If you’re interested, send us a message at hello@harbour.space and we will guide you through the next steps.

UPD: Editorial is out

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

1278A - Shuffle Hashing

Idea: Neon

Tutorial
Solution 1 (pikmike)
Solution 2 (pikmike)

1278B - A and B

Idea: Roms

Tutorial
Solution (Roms)

1278C - Berry Jam

Idea: MikeMirzayanov

Tutorial
Solution (pikmike)

1278D - Segment Tree

Idea: Neon

Tutorial
Solution (Ne0n25)

1278E - Tests for problem D

Idea: Neon

Tutorial
Solution (Ne0n25)

1278F - Cards

Idea: BledDest

Tutorial
Solution (BledDest)

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

Hello Codeforces!

On Dec/19/2019 17:35 (Moscow time) Educational Codeforces Round 78 (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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Codeforces and Harbour.Space

Hi Codeforces!

The deadline to apply for our Master’s Scholarship in Bangkok is very soon!

Don't miss your chance and apply for our progressive Master’s programs in Data Science and Cyber Security in just 3 steps:

1. Submit your CV to see if you are an eligible candidate for the scholarship
2. If your profile matches the requirements, one of our admissions officers will get in touch with you
3. Apply for the program, pay the 125€ application fee, pass a series of interviews, and if you’re accepted, pack your bags to Bangkok!

And if you know someone who might be interested in Digital Marketing, High Tech Entrepreneurship, Interaction Design or FinTech, send them our way!

MORE INFO→

Also, don’t forget to read our newest blogs!

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 HIR180 6 106
2 neal 6 162
3 receed 6 172
4 Geothermal 6 174
5 cerberus97 6 179

Congratulations to the best hackers:

Rank Competitor Hack Count
1 Akulyat 24
2 hoke_t 20
3 dhxh 18:-1
4 vovanstrr 14
5 WNG 13:-1
255 successful hacks and 458 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A Dalgerok 0:01
B neal 0:04
C HIR180 0:08
D Tutis 0:17
E gxnncrx1993 0:20
F jqdai0815 0:07

UPD: Editorial is out

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

1260A - Heating

Idea: adedalic

Tutorial
Solution (adedalic)

1260B - Obtain Two Zeroes

Idea: Roms

Tutorial
Solution (Roms)

1260C - Infinite Fence

Idea: adedalic

Tutorial
Solution (adedalic)

1260D - A Game with Traps

Idea: BledDest

Tutorial
Solution (BledDest)

1260E - Tournament

Idea: Roms

Tutorial
Solution (Roms)

1260F - Colored Tree

Idea: RDDCCD

Tutorial
Solution (RDDCCD)

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

Hello Codeforces!

On Nov/27/2019 16:50 (Moscow time) Educational Codeforces Round 77 (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 problems and 2 hours to solve them.

The problems were invented and prepared by ZiXuan Yan RDDCCD, Roman Roms Glazov, 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!

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

Hello Codeforces!

This week we have two new blog posts and a reminder of our Data Science Scholarship!

BLOG:

OUR SCHOLARSHIP

We are offering fully-funded international scholarships for exceptional tech specialists from around the world. Accelerate your career by becoming an industry expert capable of making key data-driven decisions that add value and drive innovation within tech industries.

Harbour.Space University has partnered with SCG, a leading business conglomerate in the ASEAN region, to offer exceptional tech specialists the opportunity to work and study in two of the most dynamic and vibrant cities in the world. Join our progressive two-year program based in Bangkok, with 6 of the 24 months in Barcelona, to develop the international mindset needed to accelerate your career and redefine how data drives the businesses of the future.

Codeforces and Harbour.Space

Tuition fee:

2 years | €45,800

Education:

3 hours of study per day | 15h per week

Work Experience:

4 hours of internship per day at SCG | 20h per week

Living Allowance:

€16,800 euros | €700 per month living allowance


APPLY HERE→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 twitch.tv_wookje 6 209
2 Tweetuzkokodayo 6 219
3 saketh 6 220
4 mango_lassi 6 280
5 LJFOO7 6 288

Congratulations to the best hackers:

Rank Competitor Hack Count
1 Rian_5900 60:-3
2 blaction 13
3 Fyodor 14:-5
4 wolfy6 11
5 brunomont 11:-2
216 successful hacks and 246 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A dorijanlendvaj 0:01
B dorijanlendvaj 0:02
C dorijanlendvaj 0:07
D lzoi.win 0:19
E PinkRabbitAFO 0:16
F Kuroni 1:19

UPD: Editorial is out

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

1257A - Два враждующих ученика

Idea: Roms

Tutorial
Solution (adedalic)

1257B - Волшебная палочка

Idea: BledDest

Tutorial
Solution (Ne0n25)

1257C - Задоминированный подмассив

Idea: adedalic

Tutorial
Solution (adedalic)

1257D - Очередная задача на сражение с монстрами

Idea: Roms

Tutorial
Solution (Roms)

1257E - Контест

Idea: vovuh

Tutorial
Solution (BledDest)

1257F - Сделай их похожими

Idea: vovuh

Tutorial
Solution (BledDest)

1257G - Множество делителей

Idea: adedalic

Tutorial
Solution (adedalic)

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

Hello Codeforces!

On Nov/13/2019 17:35 (Moscow time) Educational Codeforces Round 76 (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 7 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Attention Codeforces!

Calling on all tech disruptors, data specialists and computer science pioneers.
We are offering fully-funded international scholarships for exceptional tech specialists from around the world. Accelerate your career by becoming an industry expert capable of making key data-driven decisions that add value and drive innovation within tech industries.

Harbour.Space University has partnered with SCG, a leading business conglomerate in the ASEAN region, to offer exceptional tech specialists the opportunity to work and study in two of the most dynamic and vibrant cities in the world. Join our progressive two-year program based in Bangkok, with 6 of the 24 months in Barcelona, to develop the international mindset needed to accelerate your career and redefine how data drives the businesses of the future.

Codeforces and Harbour.Space

Tuition fee:

2 years | €45,800

Education:

3 hours of study per day | 15h per week

Work Experience:

4 hours of internship per day at SCG | 20h per week

Living Allowance:

€16,800 euros | €700 per month living allowance


APPLY HERE→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 neal 7 182
2 kmjp 7 216
3 saketh 7 218
4 KrK 7 225
5 ivan100sic 7 244
5 pwild 7 244

Congratulations to the best hackers:

Rank Competitor Hack Count
1 Decayed 39:-10
2 liouzhou_101 59:-58
3 dzhiblavi 15
4 Rian_5900 31:-40
5 Fyodor 10:-2
278 successful hacks and 501 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A amnesiac_dusk 0:00
B Siberian 0:02
C Bohun 0:03
D LJC00118 0:16
E jjang36524 0:23
F TripleM5da 0:19
G black_horse2014 0:19

UPD: Editorial is out

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

1251A - Broken Keyboard

Idea: BledDest

Tutorial
Solution (Ne0n25)

1251B - Binary Palindromes

Idea: adedalic

Tutorial
Solution (adedalic)

1251C - Minimize The Integer

Idea: Roms

Tutorial
Solution (Roms)

1251D - Salary Changing

Idea: Roms

Tutorial
Solution (Roms)

1251E1 - Voting (Easy Version)

1251E2 - Voting (Hard Version)

Idea: Roms

Tutorial
Solution (Roms)

1251F - Red-White Fence

Idea: Neon and BledDest

Tutorial
Solution (BledDest)

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

Hello Codeforces!

On Oct/24/2019 18:05 (Moscow time) Educational Codeforces Round 75 (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 7 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hello Codeforces,

We would like to invite all of you to Mike Mirzayanov's course Advanced Algorithms and Data Structures, which will take place in Barcelona, from the 6th to 24th of January, 2020.

The course will consist of three weeks of training, 5 training days each week. The program includes daily lectures and practical exercises. It will be quite educational, insightful and entertaining!

And you will have the opportunity to meet and talk with Mike, who will be happy to share his knowledge and stories about the history of Codeforces.

We are happy to offer a special price of 1,000 EUR* for all Codeforces users.

Register on the page below and we will contact you for the next steps. Hurry up! Only 10 spots available.

* The cost does not include travel or accommodation.

REGISTER HERE→

We would also like to recommend you an article published on our blog last week about the 5 reasons why traditional universities can’t keep up with humanity.

UPD: The start of the round is postponed by 30 minutes.

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 neal 7 199
2 Anadi 7 205
3 risujiroh 7 208
4 imeimi 7 229
5 jiangly 7 273

96 successful hacks and 196 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A cxk0707 0:02
B wangziji 0:05
C Bohun 0:06
D guyan 0:16
E1 TwentyOneHundredOrBust 0:15
E2 TwentyOneHundredOrBust 0:14
F Radewoosh 0:19

UPD: Editorial is out

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

1238A - Prime Subtraction

Idea: BledDest

Tutorial
Solution (BledDest)

1238B - Kill `Em All

Idea: Neon

Tutorial
Solution (Ne0n25)

1238C - Standard Free2play

Idea: adedalic

Tutorial
Solution (adedalic)

1238D - AB-string

Idea: Roms

Tutorial
Solution (Roms)

1238E - Keyboard Purchase

Idea: Roms

Tutorial
Solution (Roms)

1238F - The Maximum Subtree

Idea: Roms

Tutorial
Solution (Roms)

1238G - Adilbek and the Watering System

Idea: Neon

Tutorial
Solution (Ne0n25)

Full text and comments »

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

Hello Codeforces!

On Oct/08/2019 17:35 (Moscow time) Educational Codeforces Round 74 (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 7 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hello Codeforces,

First of all, thank you for the great feedback on our survey from the last Educational Round. Over 300 people participated, and we hope to start implementing some of your suggestions really soon.

We also wanted to let you know that we have extended the deadline for our fully-funded scholarships for Masters programs in Bangkok.

Remember, they cover the entire tuition fee as well as the cost of living expenses, so If you or someone you know are interested in technology, entrepreneurship, or design, and believe you have what it takes, we want to hear from you!

APPLY HERE→

Last, but not least, we would like to recommend an article published in our blog last week about the “Top 5 Soft Skills Every Developer Has to Have”. What do you think, do you agree with this list?

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 HIR180 7 296
2 Hoxilo 7 317
3 stasio6 7 350
4 sigma425 7 400
5 jiangly 7 405

Congratulations to the best hackers:

Rank Competitor Hack Count
1 kimbj0709 120:-19
2 Retired_NarutoElMatria 107:-111
3 baluteshih 48:-9
4 galen_colin 40:-3
5 Rian_5900 34:-13
571 successful hacks and 641 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A algo.code 0:00
B Surge 0:04
C tryasozhoper 0:17
D MarcosK 0:08
E GyojunYoun 0:09
F ksun48 0:29
G NotNight 0:51

UPD: Editorial is out

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

1221A - 2048 Game

Idea: Roms

Tutorial
Solution (Roms)

1221B - Knights

Idea: BledDest

Tutorial
Solution (PikMike)

1221C - Perfect Team

Idea: Roms

Tutorial
Solution 1 (BledDest)
Solution 2 (PikMike)

1221D - Make The Fence Great Again

Idea: Roms

Tutorial
Solution (Roms)

1221E - Game With String

Idea: Roms

Tutorial
Solution (Roms)

1221F - Choose a Square

Idea: Neon

Tutorial
Solution (Ne0n25)

1221G - Graph And Numbers

Idea: BledDest

Tutorial
Solution (BledDest)

Full text and comments »

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By awoo, history, 5 years ago, In English

First of all, I'm really sorry for the issues the round had. We paid not enough attention to make sure everything works as intented and got punished for it. That was a lesson for us, we'll do our best to keep the future rounds as clean as possible.

The problem B had an issue with the checker, solutions have been recieving wrong verdicts. Unfortunately, neither its author, nor reviewers have noticed the bug.

Can you spot it without looking in comments?

The bugged checker

It's been compiling with no warnings even with -Wall -Wextra -Wconversion flags. By no means that justifies our carelessness but the mistake was really unfortunate.

We really hope you enjoyed the problems nevertheless.

The contest will definitely be unrated for the participants affected by it.

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

Hello Codeforces!

On Sep/19/2019 17:35 (Moscow time) Educational Codeforces Round 73 (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 Roman Roms Glazov, 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!

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

Hello Codeforces,

We want to know what you think about Harbour.Space’s involvement in the Codeforces community, and how you believe we can improve.

So we created this short, 5 question survey to hear your thoughts about how we can provide you with more stuff that you’re interested in, so that we can improve your experience on Codeforces.

We really value your feedback, so it would mean a lot if you could take a minute and fill out the survey. Thanks in advance!

GO TO SURVEY→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 244mhq 7 192
2 jiangly 6 152
3 betrue12 6 187
4 I_love_Tanya_Romanova 6 196
5 pekempey 6 198

Congratulations to the best hackers:

Rank Competitor Hack Count
1 achi_basadzishvili 129:-46
2 apoorv024 87:-4
3 Abdelrahman_Elhawary 73:-31
4 phyzzmat 52:-7
5 Sherrrkhann 15:-1
544 successful hacks and 568 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A talant 0:01
B talant 0:02
C YahiaAglan74 0:04
D sys. 0:08
E 244mhq 0:31
F Benq 0:35
G Benq 1:02

UPD: Post about the issue

UPD2: Editorial is out

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

1217A - Creating a Character

Tutorial
Solution (adedalic)

1217B - Zmei Gorynich

Idea: Roms

Tutorial
Solution (Roms)

1217C - The Number Of Good Substrings

Idea: Roms

Tutorial
Solution (Roms)

1217D - Coloring Edges

Idea: BledDest

Tutorial
Solution (Roms)

1217E - Sum Queries?

Idea: BledDest

Tutorial
Solution (PikMike)

1217F - Forced Online Queries Problem

Idea: BledDest

Tutorial
Solution (PikMike)

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By awoo, 5 years ago, translation, In English

Hello Codeforces!

On Sep/05/2019 17:35 (Moscow time) Educational Codeforces Round 72 (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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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!

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

Hello Codeforces,

Harbour.Space University and UTCC are collaborating to offer graduate students from anywhere in the world a once in a lifetime opportunity: fully funded scholarships for our Masters programs in Bangkok.

These scholarships are designed to completely eliminate the barrier between exceptional talents and sophisticated education: they cover the entire tuition fee as well as the cost of living expenses, and furthermore, they provide the student the valuable experience of both studying and working at Harbour.Space University.

We’re looking for the people who are going to change the world.

If you or someone you know are interested in technology, entrepreneurship, or design, and believe you have what it takes, we want to hear from you!

APPLY HERE→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 Tropical_maid 6 212
2 Return.Hao 6 246
3 xyz100 6 272
4 YangDavid 6 280
5 Lawali 6 300

Congratulations to the best hackers:

Rank Competitor Hack Count
1 VegetableP 116:-14
2 Princ_iple 49:-1
3 racsosabe 42:-1
4 shurongwang 36
5 Megatron_99 29:-1
1432 successful hacks and 1595 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A xyz100 0:02
B talant 0:06
C Laiu 0:06
D IgorI 0:08
E mir 0:30
F Hasan0540 0:51

UPD: The editorial is out

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

1207A - There Are Two Types Of Burgers

Idea: BledDest

Tutorial
Solution (Roms)

1207B - Square Filling

Idea: BledDest

Tutorial
Solution (BledDest)

1207C - Gas Pipeline

Idea: adedalic

Tutorial
Solution (adedalic)

1207D - Number Of Permutations

Idea: Roms

Tutorial
Solution (Roms)

1207E - XOR Guessing

Idea: adedalic, Neon, BledDest

Tutorial
Solution (BledDest)

1207F - Remainder Problem

Idea: BledDest

Tutorial
Solution (BledDest)

1207G - Indie Album

Idea: adedalic

Tutorial
Solution (PikMike)

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

Hello Codeforces!

On Aug/22/2019 17:35 (Moscow time) Educational Codeforces Round 71 (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 7 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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 participants!

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

Hello Codeforces,

We are opening a new campus in Bangkok, Thailand!

We are delighted to introduce a strategic partnership between Harbour.Space University and the University of the Thai Chamber of Commerce – a collaborative effort powered by B.Grimm.

After 3 years of successfully disrupting education in Barcelona, with a unique educational model founded on active learning in entrepreneurship, technology, and design, as well as the most extraordinary academic and professional community on the planet to show for it, we are ready to bring the revolution to our new campus in Bangkok, Thailand.

Scholarships for our Bangkok campus are designed to completely eliminate the barrier between exceptional talents and sophisticated education: they cover the entire tuition fee as well as the cost of living expenses, and furthermore, they provide the student the valuable experience of both studying and working at Harbour.Space University.

Unique opportunities reserved for the most brilliant students from anywhere in the world, our scholarships are more than financial support – they are portals from your past to your future.

If you are graduating or have already completed a bachelor's degree, we are waiting for your applications for fully-funded Master's degree scholarships by the link below.

APPLY HERE→

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 hehezhou 7 235
2 pekempey 7 235
3 TadijaSebez 7 238
4 Barichek 7 241
5 FurryChina 7 247

467 successful hacks and 688 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A vintage_Vlad_Makeev 0:01
B Dalgerok 0:04
C kmjp 0:12
D KenMuse 0:13
E AkshajK 0:10
F AnotherRound 0:07
G danya.smelskiy 0:26

UPD: Editorial is out

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

1202A - You Are Given Two Binary Strings...

Idea: adedalic

Tutorial
Solution (adedalic)

1202B - You Are Given a Decimal String...

Idea: adedalic

Tutorial
Solution (adedalic)

1202C - You Are Given a WASD-string...

Idea: adedalic

Tutorial
Solution (adedalic)

1202D - Print a 1337-string...

Idea: Roms

Tutorial
Solution (Roms)

1202E - You Are Given Some Strings...

Idea: Roms

Tutorial
Solution (adedalic)

1202F - You Are Given Some Letters...

Idea: adedalic

Tutorial
Solution (PikMike)

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

Hello Codeforces!

On Aug/07/2019 17:35 (Moscow time) Educational Codeforces Round 70 (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 problems and 2 hours to solve them.

The problems were invented and prepared by Roman Roms Glazov, 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 participants!

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

Hello Codeforces!

Ready to get deep?

Take a minute and ask yourselves — what skills are I missing, that I would love to have? What are those key qualities that would take me from being a decent developer to an extraordinary one? Am I where I want to be, in terms of personal progress?

At Harbour.Space, we focus on the key technical and social requirements of the jobs of the future. Our three-week courses are designed for students to acquire and develop specific skills through seminars, workshops, projects, and case studies in a very short amount of time.

Mike Mirzayanov’s course, Advanced Algorithms and Data Structures, is a great example of this:

This, in combination with our unique academic environment, extensive professional network, and our seaside campus in the beautiful city of Barcelona, provides for a truly unique learning experience.

Interested?

Fill out the form below, get more information, and see how you can come attend Mike’s course to see what all the fuss is about!

APPLY HERE→

See you soon!

Harbour.Space

Congratulations to the winners:

Rank Competitor Problems Solved Penalty
1 CSWhisky 6 258
2 tfg 6 302
3 Sugar_fan 6 310
4 jiangly 6 338
5 Geothermal 5 195

109 successful hacks and 290 unsuccessful hacks were made in total!

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

Problem Competitor Penalty
A nantf 0:03
B Denverjin 0:11
C Geothermal 0:20
D dhxh 0:10
E lqs2015 0:19
F duxing201606 0:59

UPD: Editorial is out

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

1197A - DIY Wooden Ladder

Idea: adedalic

Tutorial
Solution (adedalic)

1197B - Pillars

Idea: BledDest

Tutorial
Solution (BledDest)

1197C - Array Splitting

Idea: Roms

Tutorial
Solution (Roms)

1197D - Yet Another Subarray Problem

Idea: BledDest

Tutorial
Solution (Roms)

1197E - Culture Code

Idea: adedalic

Tutorial
Solution (adedalic)

1197F - Coloring Game

Idea: BledDest

Tutorial
Solution (BledDest)

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