1 files changed, 52 insertions, 0 deletions
diff --git a/02/1.rkt b/02/1.rkt
new file mode 100644
index 0000000..3ccd4ad
--- /dev/null
+++ b/02/1.rkt
@@ -0,0 +1,52 @@
+#lang racket
+
+(require "../lib/utils.rkt")
+
+(define fp (open-input-file "input"))
+
+(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 (λ (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 (possible? game)
+  (if (null? game)
+      #t
+      (let ()
+        (define head (car game))
+        (if (or (> (car head) 12)    ; r
+                (> (cadr head) 13)   ; g
+                (> (caddr head) 14)) ; b
+            #f
+            (possible? (cdr game))))))
+
+(apply + (map cadr
+              (filter (λ (game)
+                        (possible? (car game)))
+                      (enumerate (map extract-game lines)))))