day 5: initial solution

5.rkt

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+#lang curly-fn racket
+
+(require "scripts/aoc.rkt")
+
+;; solution for day 5
+
+;; helper functions here
+
+(define (part1 input)
+  (apply max
+    (for/list ([line (in-list input)])
+      (match-define (list _ rowstr colstr) (regexp-match #px"^([FB]{7})([LR]{3})$" line))
+      (define row (string->number (string-replace (string-replace rowstr "F" "0") "B" "1") 2))
+      (define col (string->number (string-replace (string-replace colstr "L" "0") "R" "1") 2))
+      (+ (* row 8) col))))
+
+(define (part2 input)
+  (define seats
+    (for/list ([line (in-list input)])
+      (match-define (list _ rowstr colstr) (regexp-match #px"^([FB]{7})([LR]{3})$" line))
+      (define row (string->number (string-replace (string-replace rowstr "F" "0") "B" "1") 2))
+      (define col (string->number (string-replace (string-replace colstr "L" "0") "R" "1") 2))
+      (+ (* row 8) col)))
+
+  (for/first ([id (in-range (apply min seats) (apply max seats))]
+              #:when (and (not (member id seats))
+                          (member (add1 id) seats)
+                          (member (sub1 id) seats)))
+    id))
+
+(module+ main
+  (define input (file->lines "inputs/5"))
+  ;; part 1
+  (answer 5 1 (part1 input))
+
+  ;; part 2
+  (answer 5 2 (part2 input))
+
+  (displayln "meow"))