99 lines
3.5 KiB
Racket
99 lines
3.5 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 17
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(struct pt [x y z w] #:transparent)
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(define (part1 input)
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(define world (hash-copy input))
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(define (simulate world)
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(define new-world (make-hash))
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(define min-x (apply min (map pt-x (hash-keys world))))
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(define max-x (apply max (map pt-x (hash-keys world))))
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(define min-y (apply min (map pt-y (hash-keys world))))
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(define max-y (apply max (map pt-y (hash-keys world))))
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(define min-z (apply min (map pt-z (hash-keys world))))
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(define max-z (apply max (map pt-z (hash-keys world))))
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(for* ([x (in-range (- min-x 1) (+ max-x 2))]
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[y (in-range (- min-y 1) (+ max-y 2))]
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[z (in-range (- min-z 1) (+ max-z 2))])
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(define ct (for*/sum ([dx (in-range -1 2)]
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[dy (in-range -1 2)]
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[dz (in-range -1 2)]
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#:unless (and (zero? dx) (zero? dy) (zero? dz))
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#:when (hash-ref world (pt (+ x dx) (+ y dy) (+ z dz) 0) #f))
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1))
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(define this (pt x y z 0))
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(cond
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[(hash-ref world this #f)
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(when (or (= 2 ct) (= 3 ct))
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(hash-set! new-world this #t))]
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[else
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(when (= 3 ct)
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(hash-set! new-world this #t))]))
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new-world)
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(for ([i (in-range 6)])
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(set! world (simulate world)))
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(length (filter identity (hash-values world))))
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(define (part2 input)
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(define world (hash-copy input))
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(define (simulate world)
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(define new-world (make-hash))
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(define min-x (apply min (map pt-x (hash-keys world))))
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(define max-x (apply max (map pt-x (hash-keys world))))
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(define min-y (apply min (map pt-y (hash-keys world))))
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(define max-y (apply max (map pt-y (hash-keys world))))
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(define min-z (apply min (map pt-z (hash-keys world))))
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(define max-z (apply max (map pt-z (hash-keys world))))
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(define min-w (apply min (map pt-w (hash-keys world))))
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(define max-w (apply max (map pt-w (hash-keys world))))
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(for* ([x (in-range (- min-x 1) (+ max-x 2))]
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[y (in-range (- min-y 1) (+ max-y 2))]
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[z (in-range (- min-z 1) (+ max-z 2))]
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[w (in-range (- min-w 1) (+ max-w 2))])
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(define ct (for*/sum ([dx (in-range -1 2)]
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[dy (in-range -1 2)]
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[dz (in-range -1 2)]
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[dw (in-range -1 2)]
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#:unless (and (zero? dx) (zero? dy) (zero? dz) (zero? dw))
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#:when (hash-ref world (pt (+ x dx) (+ y dy) (+ z dz) (+ w dw)) #f))
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1))
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(define this (pt x y z w))
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(cond
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[(hash-ref world this #f)
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(when (or (= 2 ct) (= 3 ct))
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(hash-set! new-world this #t))]
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[else
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(when (= 3 ct)
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(hash-set! new-world this #t))]))
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new-world)
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(for ([i (in-range 6)])
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(set! world (simulate world)))
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(length (filter identity (hash-values world))))
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;; parse input file
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(define (parse fname)
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(define input (file->lines fname))
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(define world (make-hash))
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(for ([line (in-list input)] [y (in-naturals)])
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(for ([char (in-string line)] [x (in-naturals)])
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(when (char=? #\# char)
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(hash-set! world (pt x y 0 0) #t))))
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world)
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(module+ test
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(require rackunit)
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;; tests here
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(displayln "no tests :("))
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(module+ main
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(define input (parse "inputs/17"))
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(answer 17 1 (time (part1 input)))
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(answer 17 2 (time (part2 input)))
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(displayln "meow"))
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