refactor advent of code 2023 day 02 from c to racket

1 files changed, 49 insertions, 0 deletions

diff --git a/advent-of-code/2023/02/2.rkt b/advent-of-code/2023/02/2.rkt
new file mode 100644
index 0000000..8975a27
--- /dev/null
+++ b/advent-of-code/2023/02/2.rkt
@@ -0,0 +1,49 @@
+#lang racket
+
+(define fp (open-input-file "input"))
+
+(define (get-lines fp)
+  (let loop ((lines '()))
+    (define l (read-line fp))
+    (if (eof-object? l)
+      (reverse lines)
+      (loop (cons l lines)))))
+
+(define lines (get-lines fp))
+
+(define (extract-game line)
+  (define game-str (cadr (string-split line ":")))
+  (define sets-str (string-split game-str ";"))
+  (set! sets-str (map string-trim sets-str))
+  (map extract-set sets-str))
+
+(define (extract-set str)
+  (define r 0)
+  (define g 0)
+  (define b 0)
+  (define balls (string-split str ","))
+  (set! balls
+    (map (lambda (s)
+           (define pair (map string-trim (string-split s " ")))
+           (list (string->number (car pair)) (cadr pair)))
+         balls))
+  (let loop ((balls balls))
+    (if (null? balls)
+      '()
+      (let ()
+        (define ball (car balls))
+        (define number (car ball))
+        (define color (cadr ball))
+        (cond ((string=? "red" color) (set! r number))
+              ((string=? "green" color) (set! g number))
+              ((string=? "blue" color) (set! b number)))
+        (loop (cdr balls)))))
+  (list r g b))
+
+(define (power game)
+  (define rs (map car game))
+  (define gs (map cadr game))
+  (define bs (map caddr game))
+  (* (apply max rs) (apply max gs) (apply max bs)))
+
+(apply + (map power (map extract-game lines)))