Inspired by this blogpost

I haven't participated in a codeforces contest for more than a year with a half, and don't think that'll change in near future for blah blah blah whatever reason, I feel the same as author of the linked above blogpost, adding from myself maybe only the feeling that competitive programming is not that fun once you don't have any IOIs ahead and can be paid for time spent working, not practicing :D

For anyone interested, I'm adding the list of my problems to ever appear at Olympiads so far. Few more words here, even though being High-Effort/Low-Reward, I'm happy for taking (at least few steps on) the path of problemsetting regional/international competitions/olympiads, and would genuinely recommend it to those who finish their high school, but were OI enthusiasts.

In the order of my preference (or whichever I recalled earlier lol), not chronologically:

• Gugustiuc (guess the permutation), RMI'25, November 2025. Fun interactive problem. Surprisingly, very little number of solves in-contest.

• Kitten, IATI'25, April 2025. Loved making observations about Trees and Diameters, and formally proving the solution :) Ended up both in Senior and Junior divisions, had a decent number of solves in the Senior division.

• KiloBoom, UJGOI'26, March 2026. Honestly, one of the coolest solutions I ever came up with. Shout out to MAKMED1337 for coming up with the solution idea first and pushing me to see it too :) Btw, inspired by the MegaBonk game, try it out i guess.

• Happy, EJOI'25 Shortlisted, later used in IATI'26, April 2026. Cool simple problem, used in Junior group, you don't have to complicate the solution =)

• Sweets, EJOI'24, August 2024. My first ever problem used in an International Olympiad :)

• Mountains, UJGOI'26, March 2026. A simple div2B-difficulty problem. If you dare proof your solution, has a cool proof of optimalty.

• Beautiful Slice, UJGOI'26, March 2026. This is what happens to an otherwise healthy mind when stuck at a gas station in Slovakia for 15 hours. Genuinely don't recommend anyone try to solve or implement it :D

• Min-Max-Multiply! UJGOI'26 Qual. R1, somewhere in late 2025. Could be a cute div2 D/E?

• My other not-so-interesting problems from UJGOI Qual rounds, in particular, Round 2, and some of the problems of Round 1. Not too interesting, good for beginners, I guess?

To finish this,

Hello, Codeforces!

Just like me few contests ago, after Codeforces Round 990 (Div. 1) Wansur has finally reached the rank of GrandMaster. I am quite happy about it, so I decided to make this blog! I don't know what is his next CF goal, but I hope he can reach it (without using Magic).

Usually, people put their whole CP stories or how-to practice in such blogs, but I am not Mansur, so maybe he will write it in comments (or in some future blog).

Thanks for reading! Wansur orz!

Zdravo codeforces! RMI2024 starts tomorrow, 27 november, with contest days on 28-29.

Upd 1: Contest day 1 finished, standings: https://rmi.csacademy.com/contest/rmi-2024-day1/scoreboard/

Upd 2: Contest day 2 finished, standings: https://rmi.csacademy.com/contest/rmi-2024-day2/scoreboard/

This blog has no particular scope, so consider it just a blog for predictions, discussion, etc.

My prediction is, cadmiumky will win IOI RMI, StefanSebez orz and alinp will get a secret medal (secret will be revealed after the competition)

Also Bulgarian team will get at least 4 gold medals

Hello, Codeforces!

Similar to NemanjaSo2005, after Refact.ai Match 1 (Codeforces Round 985) I have finally reached the rank of International Master. I am quite happy about it, so I decided to make this blog! My next CF goal is to get the Grandmaster rank and I hope to do so by the end of the year (without using Magic).

Usually, people put their whole CP stories or how-to practice in such blogs, but I do not think it is necessary here (maybe in some future blog). However, I will say that such a topic is very well discussed on codeforces and you can find various advice with little searching.

Thanks for reading!

Hello codeforces! Can you give me advice on how to become expert? I'm training a lot, and getting very close to it, but i'm unable to cross the line to expert. Even though I'm trying hard (and I even got expert performance in today's round!) I'm barely able to get expert performances often. Please, those who can reach stable expert, give me advices on how to become one :(

Здраво codeforces. Today in this beautiful day alinp reached Master (so now we can talk with him). Congratulations alinp.

He worked really hard to reach this rank, for the past months i saw him solve a lot of geometry problems and skip IATI for random mathematics contests. Here is a photo of alinp training competitive programming really hard:

Now I hope alinp will not cheat at ioi and get a deserved χάλκινο medal

Hello cf people (though this post is mostly directed towards Mike and other cf admins/developers)!

Div3 and Educational rounds have 12-hour hacking phase after the contest which I find cool, but here is one thing that made me question:

Once you get hacked : 245168582, in your submission you can see "Hacked" verdict on which you can even click to see details. However, it won't show you the test itself, which usually will leave you questioning what was wrong in your solution, without answer. For me it was always a common thought that I can't view the hacking test until the end of the phase.

However, to my surprise, by simply resubmitting the code I can see the whole test unhidden...

...which basically takes away any sense behind stopping me from seeing the hack test directly by clicking here.

So what I question now, what is the actual reason for this? =)

Ping MikeMirzayanov geranazavr555

Hi codeforces! This blogpost is mostly intended for BalkanOI2023 participants.

This year BOI will be hosted in Slovenia, website, already very soon, on 29 October — 3 November.

Let's make list of participants with their respective cf handles (and attempts left, why not?)

Team Moldova:

• TimDee (0 or 1 attempts left)
• _Vanilla_ (0 or 1 attempts left)
• mesanu (0 or 1 attempts left)
• alinp (2 or 3 attempts left)

Hello everyone! RMI 2023 happened this week, 11-14 October. This blogpost is to discuss problems for those who participated onsite or in online mirror contest.

[Spoiler alert] avoid this post if you don't want spoilers for problems [/spoiler alert]

Personally I wonder whether anyone solved day1A like me, by heavily optimizing original DP solution to pass under 200ms or by precalculating all values like some of people I talked to did.

Also I'm curious about people's solutions to day2C that would get significant score.

Feel free to ask/answer/discuss in comments.

Btw I hope TimDee didn't cheat today

TLDR somehow codeforces judge is working way slower than oj.uz

Hello codeforces! As the IOI is coming closer and closer, I started upsolving some of the IOI tasks. I think, you've heard about IOI archive on codeforces.

Sadly I faced this problem (already at least twice): Same code running on oj.uz and on codeforces gets difent score. Surprisingly, smaller one belongs to cf.

As I thought, codeforces judge should be faster, no? Instead I have:

Problem IOI18_seats, TL on codeforces is 3 seconds, which should be enough for 2 seconds taking it to run on oj.uz

Another example:

Problem IOI19_rectangles, TLE'ing on codeforces as well, while passing on oj.uz .

Obviously, it's normal for unoptimal solutions not to pass, the only questions appear when same solution passes on oj.uz which is expected (at least, for me) to have slower judge?

I apologize in advance for pinging if that's not your responsibility, but PavelKunyavskiy, MikeMirzayanov, maybe it's a problem that can be fixed. Thanks!

Upd. submission links:

IOI19_rectangles: codeforces , oj.uz

IOI18_seats: codeforces , oj.uz

Hi codeforces! Does anyone know where we could see JBOI2022 live results? Or at least, results after day 1 ends?

Hello codeforces. As you could probably see in my previous posts, recently team selections ended in our country. Now the teams for IOI/BOI and EGOI are defined: IOI/BOI team:

SlavicG KrowSavcik FLEA _Vanilla_

EGOI team:

SlavicG KrowSavcik FLEA _Vanilla_

Today finished the 3rd day of team selections in Moldova.

Now I can introduce to you the Moldova IOI 2022 Team:

MDA1: SlavicG (11th Grade — 1 attempt more)

MDA2: KrowSavcik (11th Grade — 1 attempt more)

MDA3: FLEA (12th Grade — last attempt)

MDA4: _Vanilla_ (10th Grade — 2 attempts more)

edit: someone asked for grades (attempts left). Here they are

I sincerely congratulate each one of them and wish those who didn't pass it to present Moldova at next year IOI 2023.

Moldova IOI Team:

I would like to thank FLEA for RedFlea trick which helped me earn 60 more points

More photos from Team Selection:

Following tendency of previous post, vibing with SlavicG:

Did you know Team Selections for IOI/BOI in Moldova are anime rounds? Photo from Team Selections with SlavicG