Initial commit

2020/day01/day01.rkt

@@ -0,0 +1,37 @@
+#lang racket
+
+(module+ test
+  (require rackunit))
+
+(module+ main
+  (displayln "Day 1"))
+
+(define (read-input filename)
+  (map string->number (file->lines filename)))
+
+(define (part1 filename)
+  (define expenses (read-input filename))
+  (for*/last ([a (in-list expenses)]
+              [b (in-list expenses)]
+              #:final (= 2020 (+ a b)))
+    (* a b)))
+
+(module+ test
+  (check-eq? (part1 "test") 514579))
+
+(module+ main
+  (displayln (part1 "input")))
+
+(define (part2 filename)
+  (define expenses (read-input filename))
+  (for*/last ([a (in-list expenses)]
+              [b (in-list expenses)]
+              [c (in-list expenses)]
+              #:final (= 2020 (+ a b c)))
+    (* a b c)))
+
+(module+ test
+  (check-eq? (part2 "test") 241861950))
+
+(module+ main
+  (displayln (part2 "input")))