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| author | Hunky Jimpjorps <thechairman@thechairman.info> | 2024-02-02 17:05:12 -0500 |
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| committer | Hunky Jimpjorps <thechairman@thechairman.info> | 2024-02-02 17:05:12 -0500 |
| commit | 48e35ad3b0b0c62f936784e4aca70b17c3b0e3f9 (patch) | |
| tree | f59a13e0b5e80ab925220b4488c6e36b1bec660a /aoc2023-other/day-09/day-09.rkt | |
| parent | 87e9ab25ff70e215b537939a4bc23ab101f41dbe (diff) | |
| download | gleam_aoc-48e35ad3b0b0c62f936784e4aca70b17c3b0e3f9.tar.gz gleam_aoc-48e35ad3b0b0c62f936784e4aca70b17c3b0e3f9.zip | |
renaming
Diffstat (limited to 'aoc2023-other/day-09/day-09.rkt')
| -rw-r--r-- | aoc2023-other/day-09/day-09.rkt | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/aoc2023-other/day-09/day-09.rkt b/aoc2023-other/day-09/day-09.rkt deleted file mode 100644 index 5eda1eb..0000000 --- a/aoc2023-other/day-09/day-09.rkt +++ /dev/null @@ -1,32 +0,0 @@ -#lang racket - -(require advent-of-code - threading) - -(define histories - (for/list ([raw-history (in-lines (open-aoc-input (find-session) 2023 9 #:cache #true))]) - (~>> raw-history - string-split - (map string->number)))) - -(define (constant? xs) - (= 1 (length (remove-duplicates xs)))) - -(define/match (derivative xs) - [((list a b)) (list (- b a))] - [((list* a b _)) (cons (- b a) (derivative (rest xs)))]) - -(define (extrapolate xs) - (if (constant? xs) - (car xs) - (+ (last xs) (extrapolate (derivative xs))))) - -;; part 1 -(~>> histories - (map extrapolate) - (apply +)) - -;; part 2 -(~>> histories - (map (λ~> reverse extrapolate)) - (apply +)) |