DreamR's blog

By DreamR, history, 5 months ago, In English

Hello Codeforces,

I know the title sounds weird, but I'm in a position where I need some help. I'm making a video on my Youtube channel where I make a song/beat using the sounds I make while competitive programming. For instances, possible sounds could include: typing, writing/drawing, smacking my computer screen when I get "wrong answer on pretest #", drinking, etc.

I was wondering if you all had any other sounds that I could add into the beat/music I will make. Thanks!

Read more »

  • Vote: I like it
  • +44
  • Vote: I do not like it

By DreamR, history, 11 months ago, In English


As school is starting again soon I wanted to start making a video for my youtube music channel. Usually, I rap in Korean and then post my recordings and music on the channel, but this time I wanted to make a playlist for my video (basically compile a bunch of music). I wanted to make the theme of the video as something like "korean music for coding" or something like that. I was wondering what korean songs you guys listen to while programming?


btw here's the channel if anyone is curious: youtube channel link

Read more »

  • Vote: I like it
  • +6
  • Vote: I do not like it

By DreamR, history, 2 years ago, In English

Hello Codeforces,

After taking a quick look at the blog my fellow friend farmersrice created (btw I totally support the idea of having a CP anime) I thought, hey... why not have a CP webtoon?

For those of you who don't know what Webtoons is, it is a type of digital comic owned by Naver Corporation that originated from South Korea. To learn more, visit this Wikipedia page or just contact me.

At first, Webtoons was only popular in South Korea but soon enough Webtoons got popular all over the world in the late 2000s. Webtoons are so popular at my school that even all of the teachers read it!

Here is the link to the Korean version of webtoons, and here is the English version of it.

I think that it might be cool if Codeforces could start creating their own webtoon, and I think it will get popular very quickly if we can all think of some kind of interesting storyline. Not only will competitive programming become more well-known, but you can actually make a good amount of profit if you're webtoon becomes popular. Thus, I think creating a webtoon will be very beneficial to Codeforces and the rest of the computer science world.

BTW haters please don't hate -- I am just throwing an idea out there. It's Codeforces choice to have a webtoon or not.

If someone has a good storyline for an anime or webtoon please comment!

Possible Storylines

  • The Daily Life of a Competitive Programmer
  • The Love Life of a Competitive Programmer
  • A Competitive Programmer at School
  • A Competitive Programmer at his/her Job

I don't know really... just throwing these storyline ideas out there!

Thanks for reading and happy coding! ~DreamR

PS I would make my own competitive programming for Codeforces but I honestly suck at art. xD

Read more »

  • Vote: I like it
  • +48
  • Vote: I do not like it

By DreamR, history, 2 years ago, In English

Hi Codeforces Community!

If you didn't know, then the first ever Codeforces contest was held on February 19th, 2010 and it had a total of 175 participants! (The beta round) Think about how much Codeforces has grown over the past 9 years! (It's grown REALLY rapidly and there are a ton of registered users and Codeforces is really well known)

I guess it is sort of ironic that I am writing this blog because I haven't been on Codeforces for even a month xD

Anyways, Happy Anniversary! We love you Codeforces! <3

Show and express your love and support towards Codeforces down below in the comments!

Read more »

  • Vote: I like it
  • +59
  • Vote: I do not like it

By DreamR, history, 2 years ago, In English

Hello Codeforces,

I would like to introduce you to:

Recently combined with ShareLaTeX, Overleaf has been updated to a new version and is used widely among students and teachers.

What is Overleaf?

Overleaf is a website where you can start using LaTeX on the go, possibly helping you to write an essay, paper, or proof. You can learn what LaTeX by checking out the following websites:

  1. Wikipedia
  2. Guide

Why use Overleaf?

There's nothing complicated for you to install, you can start using Overleaf the instant you register for an account. You can also collaborate with classmates, teachers, friends, etc — Your collaborator doesn't even need an account! There are also many templates available on Overleaf that you could use. Lastly, Overleaf supports almost all LaTeX features, such as inserting images, bibliographies, equations, etc. You can read more about the exciting things you can accomplish in Overleaf by checking out these guides.

How to register

Just register like you did for Codeforces! Make a username, password, and then link your account to an email, and then your all set! Start using LaTeX!

Homepage: Overleaf

I'm already aware that many of you probably know about Overleaf, as it is well known and popular throughout the world, but for the other users who yet don't know about Overleaf or LaTeX I hope this will help you out in any sort of way. <3

If you have any difficulties or have questions, please message me and I will get back to you as soon as possible.

AoPS is also a good site to ask questions and explore deeper into LaTeX!

Thanks for reading!


P.S: LaTeX is usually used for math-related topics but you can still use it to show your work or prove something in your code. Trust me! There is a 100% guarantee that Overleaf will be helpful. :)

In the future I will be sharing other LaTeX online editors.

Read more »

  • Vote: I like it
  • +54
  • Vote: I do not like it

By DreamR, history, 2 years ago, In English

Hi there!

I recently thought up a very interesting problem, so I will introduce it to you guys.

One day, when I (Dreamr) was in the pool teaching a swimming lesson held in the neighborhood pool center, I was thinking about the inefficiency of the process for the upcoming exam. There are n (1 <= n <= 100,000) pools in the swimming center and m(1 <= m <= 100,000) students who would participate in the exam.

Dreamr, the owner of the center, already knew about the duration (every di <= 10^9) of each student that will take the exam. Only one student at a time can be in one pool and the test can be run simultaneously in multiple pools. Dreamr is a really lazy person, so he hopes to make the minimum of the maximum time of each pool's total used time. However, Dreamr is not a super bright person. Thus, Dreamr only wants to know a solution that is close to the actual answer: Your output can be smaller than or equal to 2 times the correct optimal solution. (Extra challenge: In the comments try to prove why the problem would be impossible to solve if you have to get the actual optimal solution/answer.)

Please help Dreamr solve this challenging problem.


2 5

3 3 5 7 8



3 3 7

5 8


In the first test case, there are 2 pools and 5 people. If Dreamr assigns 3, 3, 5 to the first pool and 7, 8 to the second pool, then it takes 11 and 15 minutes, respectively, so the maximum time is 15. If Dreamr assigns 3, 3, 7 to the first pool and 5, 8 to the second pool, then it takes both 13 minutes, so the maximum time is 13.

13 < 15 so the optimal solution would be 13.

Thus, your output can be smaller than or equal to 26 in this case.

Sorry for my bad English <3

Thanks for reading and happy problem-solving!


Read more »

  • Vote: I like it
  • +13
  • Vote: I do not like it