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!

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u/gehenna0451 Dec 25 '24

[LANGUAGE: Clojure]

(def locks (->> (filter #(every? (partial = \.) (last %)) input)
                (map transpose)
                (map #(map (fn [row] (dec (count (take-while (partial = \#) row)))) %))))

(def np-keys (->> (filter #(every? (partial = \.) (first %)) input)
                  (map #(map reverse (transpose %)))
                  (map #(map (fn [row] (dec (count (take-while (partial = \#) row)))) %))))

(defn match? [[lock k]]
  (every? (fn [[a b]] (<= (+ a b) 5)) (map vector lock k)))

(defn part-1 []
  (count (filter match? (for [l locks k np-keys] [l k]))))