prep for 2023, renaming for consistency

1 files changed, 22 insertions, 0 deletions

diff --git a/aoc2022/day-06/day-06.rkt b/aoc2022/day-06/day-06.rkt
new file mode 100644
index 0000000..1c167a6
--- /dev/null
+++ b/aoc2022/day-06/day-06.rkt
@@ -0,0 +1,22 @@
+#lang racket
+
+(require advent-of-code
+         (only-in algorithms sliding))
+
+(define buffer (fetch-aoc-input (find-session) 2022 6))
+
+(define (find-marker data type)
+  (define n
+    (case type
+      [(start-of-packet) 4]
+      [(start-of-message) 14]))
+  (for/first ([chunk (in-list (sliding (string->list data) n))]
+              [i (in-naturals n)]
+              #:unless (check-duplicates chunk))
+    i))
+
+;; part 1
+(find-marker buffer 'start-of-packet)
+
+;; part 2
+(find-marker buffer 'start-of-message)