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-rw-r--r--2015/day-02/day-02.rkt48
1 files changed, 48 insertions, 0 deletions
diff --git a/2015/day-02/day-02.rkt b/2015/day-02/day-02.rkt
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+++ b/2015/day-02/day-02.rkt
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+#lang racket
+(require "../../jj-aoc.rkt"
+ threading
+ racket/struct)
+
+(struct present (l w h) #:transparent)
+
+(define presents
+ (for/list ([size-string (in-lines (open-day 2 2015))])
+ (~> size-string
+ (string-split "x")
+ (map string->number _)
+ (apply present _))))
+
+;; part 1
+(define (paper-area p)
+ (define main-area
+ (~> p
+ struct->list
+ (combinations 2)
+ (map (λ~> (apply * 2 _)) _)
+ (apply + _)))
+ (define slack-area
+ (~> p
+ struct->list
+ (sort <)
+ (take 2)
+ (apply * _)))
+ (+ main-area slack-area))
+
+(for/sum ([p (in-list presents)]) (paper-area p))
+
+;; part 2
+(define (ribbon-length p)
+ (define ribbon-around-box
+ (~> p
+ struct->list
+ (sort <)
+ (take 2)
+ (map (λ~> (* 2)) _)
+ (apply + _)))
+ (define ribbon-for-bow
+ (~> p
+ struct->list
+ (apply * _)))
+ (+ ribbon-around-box ribbon-for-bow))
+
+(for/sum ([p (in-list presents)]) (ribbon-length p)) \ No newline at end of file