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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,
; '("███ ████ ████ █ █ ████ ████ █ █ ██ "
; "█ █ █ █ █ █ █ █ █ █ █ █ "
; "█ █ █ ███ ██ ███ ███ ████ █ █ "
; "███ █ █ █ █ █ █ █ █ ████ "
; "█ █ █ █ █ █ █ █ █ █ █ █ "
; "█ █ ████ ████ █ █ ████ █ █ █ █ █ ")
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