Advent of Code 2025: A Kotlin Playground

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Join us live for five days of Advent of Code puzzles and five Kotlin livestreams on December 1-5. Solve puzzles in Kotlin with the help of experts from the Kotlin team and fun community guests, climb the leaderboards, learn new tricks, and get a chance to win some prizes along the way!

Here’s what we’ve planned for 2025:

• From December 1-5, join Sebastian Aigner, Kotlin Developer Advocate, and daily livestreams with special guests as they explore solutions and share Kotlin tips.
• Hang out with the collaborative Kotlin community Kotlinlong SlackWhere people post signs, discuss viewpoints, and learn from each other.
• Participate in our Kotlin leaderboard for a chance to win special prizes – both for top performers and active community members who share their Kotlin solutions.

Join us for this JetBrains celebration tradition and try to solve our Kotlin puzzles this year!

If you enjoy a little friendly competition, you can participate in our Kotlin leaderboard on adventofcode.com.

We will give away special rewards for top performers and additional rewards for randomly selected participants who share their solutions using GitHub. aoc-2025-in-kotlin Subject.

go to leaderboard Visit the Arrival Code section of your profile and enter one of the invite codes below:

• Leaderboard 1: 2343137-c975ff11
• Leaderboard 2: 2553918-98f6b5ed
• Leaderboard 3: 2076885-6961eed5

Some useful resources to get you started:

Do you want to join the race for a special entry of code in the Kotlin Awards? Here’s what you need to do:

1. Solve at least three puzzles of Code 2025’s Arrival using Kotlin.
2. Publish your solution to a repository on GitHub and add topics aoc-2025-in-kotlin By:

• Opening my repository on GitHub.
• Clicking the gear icon (⚙️) in the upper right corner of the repository page.
• being added aoc-2025-in-kotlin In Subject Field.

3. Make sure we can contact you through your GitHub profile by including an email address, X handle, or BlueSky username.

This helps us find your solutions and enter you into the prize draw!

Join us for the arrival of Code!

We’re excited to spend another Advent season solving puzzles, exploring Kotlin, and celebrating clever solutions together.

Have fun coding and see you at Advent of Code in Kotlin!