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!
