Greetings Codeforces!
First things first, we would like to thank everyone who participated in the previous eleven Kotlin Heroes competitions: Episode 1, Episode 2, Episode 3, Episode 4, Episode 5: ICPC Round, Episode 6, Episode 7, Episode 8, Episode 9, Episode 10 and Episode 11.
Kotlin Heroes is a great way to play around with Kotlin’s features, learn something new, and practice using the language by solving fun problems. It is great for programmers of any level!
We invite you to join the practice round, where you can improve your algorithmic problem-solving skills and complete training problems. In this round, all the solutions are open and you can request hints if you’re stuck.
Here are some things you can do to help you refresh your knowledge of Kotlin and learn more about competitive programming while you practice:
- Review our Kotlin solutions for the Advent of Code algorithmic puzzles.
- Read our competitive programming tutorial.
- Watch the videos from our Kotlin in Competitive Programming YouTube playlist.
- Look at the problems from the previous practice rounds.
On April 7, 2025, the real challenge begins! Kotlin Heroes: Episode 12 will last 2 hours 30 minutes and will feature a range of problems – from simple tasks anyone can solve to tricky challenges for seasoned competitive programmers.
The contest will contain at least one interactive problem, so we strongly recommend that you familiarize yourself with them — for example, by solving problem F from the practice round and/or reading the Codeforces guide for interactive problems. The flush operation in Kotlin is done by calling System.out.flush().
The use of AI-based tools during the main contest is strictly limited. To find out the guidelines for proper AI use, what is allowed and what is prohibited, please read the post "Rule Restricting the use of AI". Improper use of AI tools during the main contest may result in disqualification.
Prizes:
The top three winners will receive cash prizes of $512, $256, and $128 (or rewards of equivalent value), respectively. The top 50 participants will win a Kotlin Heroes T-shirt and an exclusive Kotlin sticker, and all competitors who solve at least one problem will be entered into a raffle for one of 50 Kotlin Heroes T-shirts.
Please note that we are not able to ship prizes to any country, state, province, or territory subject to comprehensive OFAC sanctions, including Belarus, Cuba, Iran, North Korea, Russia, Syria, or the Crimea, Donetsk, or Luhansk regions. For complete the list, please visit this page.
Best of luck to everyone!
UPD: You can find the editorial here. Thank you for participation!
Could you please tell me if this contest is rated? I'm new to Codeforces and don't know whether these "special" contests is rated or not.
By the way, GL & HF!
Yes, it is an unrated contest on Codeforces. While it provides a great opportunity to practice and compete... it does not affect your Codeforces rating. These "special" contests are designed to encourage learning and participation... especially for those interested in Kotlin programming.
GL you too..... :)
Thanks a lot for the clarification! That makes sense — it’s good to know these kinds of contests are more for learning and fun rather than ratings. I’ll definitely still give it a shot and try to learn as much as I can.
Appreciate your help — GL & HF to you too! :)
I want to try it by C++ language. Can have a way to do this by c++?(sorry i'm not good at English)
Yes.... you can try this contest by using C++ language...if the contest allows submissions in multiple programming languages...Based on the announcement , Kotlin Heroes: Episode 12 is designed to encourage participants to explore and practice Kotlin. However, for most contests on platforms like Codeforces, multiple programming languages, including C++, are often allowed. To confirm if C++ can be used for this competition, you'd need to check the contest rules and submission guidelines on the official competition page.
Hope this will help you... :) GL... :)
Thanks
Ignore the other comment, Kotlin Heroes only allows submissions in Kotlin, hence the name
Is it allowed to ask AI for some specific syntax help? e.g. I ask how to take an array input or how to define a function.
Yes, but when some other participant`s submission implemented same type of implementation is copied from AI or other resources that are matched then this approach giving plagiarism. Yes you can prove after contest but this is breaks codeforce policy.
Already a few minutes into the contest, and I see at least 3 people who are cheating
UPDT: apparently, the other languages were allowed at the first minutes at the contest (as a mistake)
Damn...Spent 45 minutes trying to optimize F, but it turned out that kotlin 1.9 much slower than 1.7. Then resubmitted with kotlin 1.7 and got AC
It was a good contest, thanks to all my friends.
Hi, could you please make all the past (or practice) kotlin round upsolvable?
I have written a short intro for running kotlin programs for competitive programming + solutions to the first 5 problems.
Solutions [A to E] for "Kotlin Heroes: Episode 12"
Looking forward to hear for solutions [F to I].
Where are the results for the raffle draw gonna be announced? I really hope to get one.
When the winners of prizes will be announced?
Are the lucky 50 T-Shirt winners announced?
Not yet, BledDest, when the results are going to be announced? 2 weeks passed already
BledDest, About 203 days ago, right after Kotlin Heroes 11, I won a T-shirt that still has not arrived. I am not begging for free swag, but the idea that winners are still waiting six months later is pretty hilarious. Did we actually run out of stocks? And while we are on the subject, do we have enough shirts ready for Kotlin Heroes 12? Because if fulfillment for episode 11 is this slow, I am curious how you will handle episode 12!
Can you saying how we will know that tshirt is arrived. They inform us on email or any other?
My shirt never arrived…
but honestly, I don’t even care anymore. With all the unfair things happening around us every day, this feels too small to even matter.
Bro there is some issue. You can contact directly to the codeforce for this there is any technical problem.
I was a winner of Kotlin Heroes 11 and it has been almost a year with no contact, that is crazy xD. I don’t know anything about Heroes 12 or later either, ts so corny.
umm i can talk about this ig ... i won a shirt in the kotlin heroes 12 event and recently got a call from dhl and it has apparently arrived in my city . so it is probably gonna arrive soon
Edit : It arrived (Yay!)
Thank for information
Congrats on also getting Top 50