day 10 complete

1 files changed, 43 insertions, 0 deletions

diff --git a/2022/day-10/day-10.rkt b/2022/day-10/day-10.rkt
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+#lang racket
+
+(require advent-of-code
+         threading
+         fancy-app
+         (only-in algorithms chunks-of))
+
+(define/match (process-instruction _)
+  [((list "noop")) (list 'noop)]
+  [((list "addx" (app string->number val))) (list 'noop (cons 'addx val))])
+
+(define instructions
+  (~> (fetch-aoc-input (find-session) 2022 10)
+      (string-split "\n")
+      (map (λ~> string-split process-instruction) _)
+      (apply append _)))
+
+;; part 1
+(define interesting-times (inclusive-range 20 220 40))
+
+(define/match (evaluate-instruction _op acc)
+  [('noop _) acc]
+  [((cons 'addx n) _) (+ acc n)])
+
+(for/fold ([acc 1] [interesting-strengths 0] #:result interesting-strengths)
+          ([inst (in-list instructions)] [i (in-naturals 1)])
+  (define new-interesting
+    (if (member i interesting-times) (+ interesting-strengths (* i acc)) interesting-strengths))
+  (values (evaluate-instruction inst acc) new-interesting))
+
+;; part 2
+(for/fold ([acc 1] [pixels '()] #:result (~> pixels reverse (chunks-of 40) (map (apply string _) _)))
+          ([inst (in-list instructions)] [i (in-naturals)])
+  (define new-pixel (if (member (modulo i 40) (list (sub1 acc) acc (add1 acc))) #\█ #\space))
+  (values (evaluate-instruction inst acc) (cons new-pixel pixels)))
+
+; for my data set,
+; '("███  ████ ████ █  █ ████ ████ █  █  ██  "
+;   "█  █    █ █    █ █  █    █    █  █ █  █ "
+;   "█  █   █  ███  ██   ███  ███  ████ █  █ "
+;   "███   █   █    █ █  █    █    █  █ ████ "
+;   "█ █  █    █    █ █  █    █    █  █ █  █ "
+;   "█  █ ████ ████ █  █ ████ █    █  █ █  █ ")