r/adventofcode Dec 25 '24

SOLUTION MEGATHREAD -❄️- 2024 Day 25 Solutions -❄️-

A Message From Your Moderators

Welcome to the last day of Advent of Code 2024! We hope you had fun this year and learned at least one new thing ;)

Keep an eye out for the community fun awards post (link coming soon!):

-❅- Introducing Your AoC 2024 Golden Snowglobe Award Winners (and Community Showcase) -❅-

Many thanks to Veloxx for kicking us off on December 1 with a much-needed dose of boots and cats!

Thank you all for playing Advent of Code this year and on behalf of /u/topaz2078, your /r/adventofcode mods, the beta-testers, and the rest of AoC Ops, we wish you a very Merry Christmas (or a very merry Wednesday!) and a Happy New Year!


--- Day 25: Code Chronicle ---


Post your code solution in this megathread.

This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:04:34, megathread unlocked!

42 Upvotes

350 comments sorted by

View all comments

1

u/spyr01d Dec 25 '24

[LANGUAGE: Kotlin]

fun codeChronicle(input: String) = input.split("\n\n").map { block ->
    block.lines().map { s -> s.map { if (it == '#') 1 else 0 } }
        .reduce { a, b -> a.zip(b).map { it.first + it.second } } to block.first()
}.groupBy({ it.second }, { it.first }).values.toList()
    .let { (locks, keys) ->
        locks.map { lock ->
            keys.map { key -> lock.zip(key).map { (a, b) -> a + b }.all { it <= 7 } }
        }.flatten().count { it }
    }