day 4: sigh

4.rkt

@@ -0,0 +1,35 @@
+#lang curly-fn racket
+
+(require "scripts/aoc.rkt")
+
+;; solution for day 4
+
+(define (part1 input)
+  (for/sum ([line (in-list input)])
+    (match-define (list (cons a b) (cons c d)) line)
+    (if (or (and (>= a c) (<= b d))
+            (and (>= c a) (<= d b)))
+      1 0)))
+
+(define (part2 input)
+  (for/sum ([line (in-list input)])
+    (match-define (list (cons a b) (cons c d)) line)
+    (if (or (and (>= a c) (<= a d))
+            (and (>= c a) (<= c b))
+            (and (>= b c) (<= b d))
+            (and (>= d a) (<= d b)))
+      1 0)))
+
+(define (parse fname)
+  (for/list ([line (in-list (file->lines fname))])
+    (match-define (list l r) (string-split line ","))
+    (match-define (list a b) (string-split l "-"))
+    (match-define (list c d) (string-split r "-"))
+    (list (cons (string->number a) (string->number b))
+          (cons (string->number c) (string->number d)))))
+
+(module+ main
+  (define input (parse "inputs/4"))
+  (answer 4 1 (time (part1 input)))
+  (answer 4 2 (time (part2 input)))
+  (displayln "meow"))