this post was submitted on 09 Nov 2025
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Advent Of Code

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An unofficial home for the advent of code community on programming.dev! Other challenges are also welcome!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

Everybody Codes is another collection of programming puzzles with seasonal events.

EC 2025

AoC 2025

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๐Ÿฆ† Everybody.Codes 2025 Quest 4 Solutions ๐Ÿฆ† (programming.dev)
submitted 1 month ago by hades@programming.dev to c/advent_of_code@programming.dev
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Quest 4: Teeth of the Wind

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

Link to participate: https://everybody.codes/

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[โ€“] vole@lemmy.world 2 points 1 month ago

maaath

Scheme/Guile

(import (rnrs io ports (6)))

(define (parse-file file-name)
       (map string->number (string-split (call-with-input-file file-name get-string-all) #\newline)))

(let* ((gears (parse-file "notes/everybody_codes_e2025_q04_p1.txt")))
  (format #t "P1 Answer: ~a\n\n" (* 2025 (/ (car gears) (car (last-pair gears))))))


(let* ((gears (parse-file "notes/everybody_codes_e2025_q04_p2.txt")))
  (format #t "P2 Answer: ~a\n\n" (ceiling (* 10000000000000 (/ (car (last-pair gears)) (car gears))))))


(define (parse-file-p3 file-name)
       (map
              (lambda (line) (map string->number(string-split line #\|)))
              (string-split (call-with-input-file file-name get-string-all) #\newline)))
(let* ((gears (parse-file-p3 "notes/everybody_codes_e2025_q04_p3.txt")))
  (format #t "P2 Answer: ~a\n\n"
          (floor (* 100
             (apply * (map (lambda (gear) (if (= 1 (length gear)) 1 (/ (cadr gear) (car gear)))) gears))
             (/ (caar gears) (caar (last-pair gears)))))))