58 lines
1.4 KiB
Racket
58 lines
1.4 KiB
Racket
#lang curly-fn racket
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(require "scripts/aoc.rkt")
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;; solution for day 11
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(define (expand universe [amount 1])
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(define width
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(add1 (apply max (set-map universe car))))
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(define height
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(add1 (apply max (set-map universe cdr))))
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(define (has-y? y)
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(for/or ([pt (in-set universe)])
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(= (cdr pt) y)))
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(define (has-x? x)
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(for/or ([pt (in-set universe)])
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(= (car pt) x)))
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(define empty-rows
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(for/list ([y (in-range height)]
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#:unless (has-y? y))
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y))
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(define empty-cols
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(for/list ([x (in-range width)]
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#:unless (has-x? x))
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x))
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(for/set ([pt (in-set universe)])
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(define x-offset (count #{< % (car pt)} empty-cols))
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(define y-offset (count #{< % (cdr pt)} empty-rows))
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(cons (+ (car pt) (* amount x-offset)) (+ (cdr pt) (* amount y-offset)))))
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(define (part1 input [amount 1])
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(define expanded (expand input amount))
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(/ (for*/sum ([a (in-set expanded)] [b (in-set expanded)])
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(+ (abs (- (car a) (car b)))
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(abs (- (cdr a) (cdr b)))))
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2))
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(define (part2 input)
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(part1 input (sub1 1000000)))
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(define (parse fname)
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(for/set ([line (in-list (file->lines fname))] [y (in-naturals)]
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#:do []
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[char (in-string line)] [x (in-naturals)]
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#:when (eq? char #\#))
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(cons x y)))
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(module+ main
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(define input (parse "inputs/11"))
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(answer 11 1 (time (part1 input)))
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(answer 11 2 (time (part2 input)))
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(displayln "meow"))
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