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day 17: more cleanup...

This commit is contained in:
xenia 2020-12-17 01:07:02 -05:00
parent a0bf7d0039
commit e7d9c9d0d3
1 changed files with 9 additions and 22 deletions
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31
17.rkt
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@ -26,30 +26,22 @@
(define nearby/3d (filter #{zero? (pt-w %)} nearby/4d))
(define (calc-bounds world)
(define (helper getter reducer)
(apply reducer (set-map world getter)))
(define (helper2 reducer)
(apply pt (map #{helper % reducer} pt-getters)))
(values (helper2 min) (helper2 max)))
(define (helper reducer)
(apply pt (map #{apply reducer (set-map world %)} pt-getters)))
(values (helper min) (helper max)))
(define (simulate world use-w?)
(define new-world (mutable-set))
(define-values [lower upper] (calc-bounds world))
(define nearby (if use-w? nearby/4d nearby/3d))
(for ([pt (in-pts lower upper use-w?)])
(define ct
(for*/sum ([nb (in-list nearby)])
(if (set-member? world (pt+ pt nb)) 1 0)))
(when (if (set-member? world pt) (<= 2 ct 3) (= 3 ct))
(set-add! new-world pt)))
new-world)
(for*/set ([pt (in-pts lower upper use-w?)]
[ct (in-value (stream-count #{set-member? world (pt+ pt %)} (in-list nearby)))]
#:when (if (set-member? world pt) (<= 2 ct 3) (= 3 ct)))
pt))
(define (simulate/times world times use-w?)
(set-count
(for/fold ([world world]) ([_ (in-range times)])
(simulate world use-w?))))
(set-count (for/fold ([world world]) ([_ (in-range times)])
(simulate world use-w?))))
(define part1 #{simulate/times % 6 #f})
(define part2 #{simulate/times % 6 #t})
@ -64,11 +56,6 @@
(set-add! world (pt x y 0 0)))))
world)
(module+ test
(require rackunit)
;; tests here
(displayln "no tests :("))
(module+ main
(define input (parse "inputs/17"))
(answer 17 1 (time (part1 input)))