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| author | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
|---|---|---|
| committer | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
| commit | 8777ff071f7bb37631baa7b6717ad29961e50911 (patch) | |
| tree | 6d59c4ed58e454b960339c3d1151f0a879e8d7cb /aoc2023-racket/day-09/day-09.rkt | |
| parent | 6156a9ef7be4012063a042aafb4e9b0d7eadde8e (diff) | |
| download | gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.tar.gz gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.zip | |
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Diffstat (limited to 'aoc2023-racket/day-09/day-09.rkt')
| -rw-r--r-- | aoc2023-racket/day-09/day-09.rkt | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/aoc2023-racket/day-09/day-09.rkt b/aoc2023-racket/day-09/day-09.rkt deleted file mode 100644 index 5eda1eb..0000000 --- a/aoc2023-racket/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 +)) |