Quest 8: The Art of Connection

  • 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/

  • vole@lemmy.worldEnglish
    2·
    4 days ago

    Scheme/Guile

    Takes about 5 seconds.

    (import (rnrs io ports (6))
        (srfi srfi-1))
#!curly-infix

(define (parse-file file-name)
  (let ((sequence (map string->number (string-split (string-trim-both (call-with-input-file file-name get-string-all)) #\,))))
    (zip sequence (cdr sequence))))

(let loop ((sequence (parse-file "notes/everybody_codes_e2025_q08_p1.txt")) (count 0))
  (if (null? sequence)
      (format #t "P1 Answer: ~a\n\n" count)
      (loop (cdr sequence) (+ count (if (and last (eq? (modulo (- (cadar sequence) (caar sequence)) 32) 16)) 1 0)))))

(define (crosses-over? a b)
  (let ((a1 (car a))
        (a2 (cadr a))
        (b1 (car b))
        (b2 (cadr b)))
    (let ((a2 (modulo {a2 - a1} 256))
          (b1 (modulo {b1 - a1} 256))
          (b2 (modulo {b2 - a1} 256)))
      (and (not (eq? b1 0)) (not (eq? b2 0))
      (or
        (and {b1 < a2} {b2 > a2})
        (and {b1 > a2} {b2 < a2}))))))
(define (count-cross-overs sequence a)
  (let loop ((sequence sequence) (count 0))
    (if (null? sequence)
        count
        (loop (cdr sequence) (+ count (if (crosses-over? (car sequence) a) 1 0))))))
(let loop ((sequence (parse-file "notes/everybody_codes_e2025_q08_p2.txt")) (passed '()) (count 0))
  (if (null? sequence)
      (format #t "P2 Answer: ~a\n\n" count)
      (loop (cdr sequence) (cons (car sequence) passed) (+ count (count-cross-overs passed (car sequence))))))


(let ((sequence (parse-file "notes/everybody_codes_e2025_q08_p3.txt")))
  (let loop ((i 1) (greatest 0))
    (if {i > 256}
        (format #t "P3 Answer: ~a\n\n" greatest)
        (loop (1+ i) (max greatest (let loop ((j i) (greatest 0))
              (if {j > 256}
                  greatest
                  (loop (1+ j) (max greatest (count-cross-overs sequence (list i j)))))))))))