today's puzzle really makes me want proper sum types, sealed classes aren't cutting it. You can't put an enum class inside a sealed class because it can't inherit 😞

🎉*Day 13 solution thread*😈

want to see how I did i t?

I'm stuck on computation on part2, it is way too slow

👾*Day 14 solution thread*:kotlin:

Day 15 solution thread :kotlin-intensifies:

Help needed for day 14 ‼️

Day 16 solution thread :kotlin-gradient:

💥Day 17 solution thread🧠

why does x=0, y=0, z=0 switches to active after their first cycle? what are its 3 neighbors?

Day 18 solution thread

For those wondering how most of the people on the leaderboard are so fast. Those are all scripting languages (ruby and python) which replaced the operators with a different one with the impl of the intended operator, and then evaled the line

Random style question:

line.mapIndexedNotNull{ y, c -> if(c == '#') (x to y).toPoint(d) else null }

Or:

line.withIndex().filter { it.value == '#' }.map { (y, _) -> (x to y).toPoint(d) }

Day 19 solution thread

🎄Day 20 solution thread⏳

🎅 Day 21 solutions discussion

🎄 Day 22 : Solutions Thread

🎄 Day 23 : Solutions Thread

🎅 Day 24 : Solutions Thread

🎁 Day 25: Solutions Thread

Hey @todd.ginsberg you should advertise your talk

32 it seems: println((0.."100000001".toInt(2)).count { it.toString(2).let { it == it.reversed() } })

Hey folks! This year, as @Sebastian Aigner mentioned in the above blog post/video, we’re providing a GitHub Template Repository to let you quickly create an Advent of Code project within your GitHub account. Long story short, it’s available here with a README explaining what’s going on (FYI, there’ll be a giveaway going on). I’m also writing this note to ask you for a favor – I’ll be happy with any feedback before the actual contest begins so I can provide relevant patches right before. Thanks!

2^0 days until Advent of Code!

any guesses which day this year will be about Chinese reminder theorem? 🙂

Advent of Code 2021 day 1 🧵

which leaderboard are we using this year?

I’m wondering - some people are posting solutions without input parsing. IMHO that should be part of the solution. What do you think?

Is it possible to get input data onto play.kotlinlang.org somehow? That would be a nice way to share runnable solutions.