71 lines
2.3 KiB
Racket
71 lines
2.3 KiB
Racket
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#lang curly-fn racket
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(require "scripts/aoc.rkt")
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;; solution for day 23
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(define (move-opt* input times)
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(define items-map (for/vector ([i (in-range 0 (add1 (vector-length input)))])
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(if (zero? i) #f (mcons i #f))))
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(define fst (vector-ref items-map (vector-ref input 0)))
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(define lst (vector-ref items-map (vector-ref input (sub1 (vector-length input)))))
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(set-mcdr! lst fst)
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(for ([i (in-range 1 (vector-length input))])
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(define item (vector-ref items-map (vector-ref input i)))
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(define prev (vector-ref items-map (vector-ref input (sub1 i))))
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(set-mcdr! prev item))
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(define total (vector-length input))
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(define (do-round item-ref)
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(define current (mcar item-ref))
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(define top (mcdr item-ref))
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(define bottom (mcdr (mcdr top)))
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(define cset
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(let loop ([d top] [cards (set)])
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(if (eq? d bottom)
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(set-add cards (mcar d))
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(loop (mcdr d) (set-add cards (mcar d))))))
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(set-mcdr! item-ref (mcdr bottom))
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(set-mcdr! bottom #f)
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(define wanted-value (let loop ([wanted (sub1 current)])
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(cond [(zero? wanted) (loop total)]
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[(set-member? cset wanted) (loop (sub1 wanted))]
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[else wanted])))
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(define wanted-ref (vector-ref items-map wanted-value))
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(set-mcdr! bottom (mcdr wanted-ref))
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(set-mcdr! wanted-ref top)
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(mcdr item-ref))
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(for/fold ([v fst]) ([i (in-range times)])
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(do-round v))
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(vector-ref items-map 1))
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(define (part1 input)
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;; TODO: What are the labels on the cups after cup 1?
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;; unimplemented lol
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(define res (move-opt* input 100))
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(let loop ([x (mcdr res)])
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(if (eq? x res)
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""
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(string-append (number->string (mcar x)) (loop (mcdr x))))))
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(define (part2 input)
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(define rst (for/vector ([x (in-range (add1 (vector-length input)) 1000001)]) x))
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(define all (vector-append input rst))
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(define res (move-opt* all 10000000))
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(* (mcar (mcdr (mcdr res))) (mcar (mcdr res))))
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;; parse input file
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(define (parse fname)
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(define input (file->string fname))
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(list->vector (filter identity (map string->number (string-split input "")))))
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(module+ main
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(define input (parse "inputs/23"))
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(answer 23 1 (time (part1 input)))
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(answer 23 2 (time (part2 input)))
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(displayln "meow"))
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