day 6 complete

1 files changed, 24 insertions, 0 deletions

diff --git a/2022/day-06/day-06.rkt b/2022/day-06/day-06.rkt
new file mode 100644
index 0000000..4eb8323
--- /dev/null
+++ b/2022/day-06/day-06.rkt
@@ -0,0 +1,24 @@
+#lang racket
+
+(require advent-of-code
+         threading
+         (only-in relation ->list ->set)
+         (only-in algorithms sliding))
+
+(define buffer (~> (fetch-aoc-input (find-session) 2022 6)))
+
+(define (find-marker data type)
+  (define n
+    (match type
+      ['start-of-packet 4]
+      ['start-of-message 14]))
+  (for/first ([chunk (in-list (sliding (->list data) n))]
+              [i (in-naturals n)]
+              #:when (= n (~> chunk remove-duplicates length)))
+    i))
+
+;; part 1
+(find-marker buffer 'start-of-packet)
+
+;; part 2
+(find-marker buffer 'start-of-message)