Kuroni's blog

By Kuroni, history, 2 months ago, In English,

Hello everyone, this is the editorial for Codeforces Round #616 (Div. 1) and Codeforces Round #616 (Div. 2)! Along with the solution to each problem, we will have the theme and easter egg solution as well! I hope you all enjoyed our problems ( ´ ▽ ` )b

1291A - Even But Not Even

Author: 265918

Tutorial
Implementation

1291B - Array Sharpening

Author: hugopm

Tutorial
Implementation

1290A - Mind Control

Author: Ari

Tutorial
Implementation (quadratic)
Implementation (linear)

1290B - Irreducible Anagrams

Author: Ari

Tutorial
Implementation

1290C - Prefix Enlightenment

Author: hugopm

Tutorial
Implementation (preprocess with DFS)
Implementation (dynamic bipartite DSU)

1290D - Coffee Varieties (hard version)

Author: hugopm

Tutorial
Implementation

1290E - Cartesian Tree

Author: gamegame

Tutorial
Implementation

1290F - Making Shapes

Author: Kuroni

Tutorial
Implementation

Theme and easter eggs

Spoilers

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By Kuroni, history, 2 months ago, In English,

Hello Codeforces o(≧∇≦o) I'm glad to introduce you to Codeforces Round #616 (Div. 1) and Codeforces Round #616 (Div. 2), which will take place on Feb/02/2020 17:05 (Moscow time).

Each division will contain 6 problems, and you will have 2.5 hours to solve them. There might be interactive problems, feel free to learn about them here. The problems were created by 265918, Ari, Kuroni, gamegame, and hugopm.

Now, here are some people I would love to mention:

The statements were made as clear as possible for your best experiences. Moreover, we sneakily included a theme in the problemset, and each problem will have an easter egg that is the clue to the theme. If you have AC'd every problem, be sure to search for the theme(*´▽`*)

Additionally, most of us are in a Discord server dedicated to competitive programming called "AC" (this is also the motto of this contest). We will be on the server after the contest to discuss the problems with you. You can find the server here!

I wish you all have good luck and high ratings ( ´ ▽ ` )ノ

UPD1: Here is the score distribution:

  • Div. 2: 500 1000 1500 2000 2750 3000

  • Div. 1: 500 1000 1750 2500 3000 3250

UPD2: Here is the editorial, including easter egg solutions!

UPD3: Thank you everyone for participating :D Here are the final standings:

Div. 1:

  1. tourist

  2. fateice

  3. ksun48

  4. Um_nik

  5. WZYYN

Div. 2:

  1. izone

  2. Infoshoc

  3. CouponKaka-ChutteNahiHai

  4. lzh12139

  5. liqing

Thank you everyone and I hope to see you again!

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By Kuroni, history, 9 months ago, In English,

Disclaimer: Please don't try this at home. I just find this occasion quite hilarious and want to share with you guys :D

So yesterday I was hanging out with my folks, and there were some mild alcohol here and there (I drank some apple cider, please don't call the police I just reached 18) and I was a bit drowsy but definitely not drunk. I was just chilling when I checked on my phone and realized it was a mere 7 minutes until Codeforces Round #573 (Div. 1). If it was for any normal human being, they would probably skipped the contest and continue the fun. However, because I am not drunk at all, I decided that I should run home and participate. So I excused myself out of the party and sprinted as fast as I can.

On the path back home, there were 2 paths, one is clear and nicely lighted but a little bit further, and one involved running through a badly-lighted park but it was shorter in distance. As a programmer, I applied the Dijkstra algorithm immediately and sprinted through the park with maximum power. Little did I know, the shorter path does not always have the lower weight. There was a giant boulder in the middle of the park, and since the park was a little dark and I am definitely not drunk, I scratched my knee onto the boulder. It kinda hurt, but I just shrugged and ran through the rest of the park. Upon reaching home, I was greeted with this (mild bleeding warning).

However, it turns out my dedication was paid off, since I probably peaked my all-time performance, solving 4 problems in div 1 for the first time and at one point even reached the 8th place with a +221 predicted delta. There's not much to say afterwards, I regained my grandmaster status with no failed system test :D

So you could say I literally traded my red blood for my red grandmaster status. Please don't do this unless you are definitely not drunk.

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By Kuroni, history, 11 months ago, In English,

Hello everyone, this is the editorial for Codeforces Round #558 (Div. 2). I hope you enjoy the problem as well as I did!

1163A - Eating Soup

Author: _iloveNQ_

Tutorial
Implementation

1163B2 - Cat Party (Hard Edition)

Author: _Shirone_

Tutorial
Implementation

1163C2 - Power Transmission (Hard Edition)

Author: LunarStellarshot

Tutorial
Implementation

1163D - Mysterious Code

Author: _Kuroni_

Tutorial
Implementation

1163E - Magical Permutation

Author: _Kuroni_

Tutorial
Implementation
Implementation with DFS

1163F - Indecisive Taxi Fee

Author: _Kuroni_

Tutorial
Implementation

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By Kuroni, history, 11 months ago, In English,

Hi Codeforces!

I'm glad to introduce you to Codeforces Round #558 (Div. 2), which will take place on May/09/2019 18:05 (Moscow time).

You will have 6 problems and 2 hours to solve them. Two problems will have subtasks. Round will be rated for everyone with rating below 2100. Participants from the first division can also participate out of competition as usual.

The problems were prepared by me, _iloveNQ_, _Shirone_, and LunarStellarshot. I would like to thank _kun_ for his immense help during the round preparation, 300iq, mohammedehab2002, and Um_nik for testing them, and of course MikeMirzayanov for the Codeforces and Polygon platforms.

In the contest, you will meet Kuro, Shiro, Katie, and Selena, the four naughty but smart cats who love playing and asking questions. I hope you will find our problems interesting.

I will be in the community Discord server after the contest to discuss the problems with you. You can find the server here!

Good luck!

UPD1: Problem B and C will have 2 subtasks. The scoring distribution will be 500 — (750 + 500) — (1000 + 750) — 2250 — 2750 — 3250.

UPD2: The contest will be delayed by 15 minutes due to technical reasons. Sorry for the inconvenience :(

UPD3: Final standings!

Div. 1:

  1. ainta (the only contestant to finish all problems!)

  2. dreamoon_love_AA

  3. hank55663

  4. tfg

  5. pmnox

Div. 2:

  1. xht37

  2. Ekoos

  3. beka_asd

  4. bbao69

  5. OIerDb

The editorial is available here. Thank you for participating!

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