prep for 2023, renaming for consistency

1 files changed, 26 insertions, 0 deletions

diff --git a/aoc2015/day-02/day-02.rkt b/aoc2015/day-02/day-02.rkt
new file mode 100644
index 0000000..579fd00
--- /dev/null
+++ b/aoc2015/day-02/day-02.rkt
@@ -0,0 +1,26 @@
+#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))