66 lines
1.8 KiB
Racket
66 lines
1.8 KiB
Racket
#lang curly-fn racket
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(require "scripts/aoc.rkt")
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;; solution for day 8
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(define (g-ref grid y x)
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(vector-ref (vector-ref grid y) x))
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(define (g-size grid)
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(values (vector-length grid) (vector-length (vector-ref grid 0))))
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(define (part1 grid)
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(define-values [h w] (g-size grid))
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(define (visible? y x)
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(define v (g-ref grid y x))
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(cond
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[(= 0 y) #t]
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[(= 0 x) #t]
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[(= (sub1 h) y) #t]
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[(= (sub1 w) x) #t]
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[else
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(or
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(for/and ([x* (in-range 0 x)])
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(< (g-ref grid y x*) v))
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(for/and ([x* (in-range (add1 x) w)])
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(< (g-ref grid y x*) v))
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(for/and ([y* (in-range 0 y)])
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(< (g-ref grid y* x) v))
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(for/and ([y* (in-range (add1 y) h)])
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(< (g-ref grid y* x) v)))]))
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(for*/sum ([x (in-range w)] [y (in-range h)] #:when (visible? y x))
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1))
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(define (part2 grid)
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(define-values [h w] (g-size grid))
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(define (scenic-score y x)
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(define v (g-ref grid y x))
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(*
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(for/sum ([x* (in-range (sub1 x) -1 -1)] #:final (>= (g-ref grid y x*) v))
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1)
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(for/sum ([x* (in-range (add1 x) w)] #:final (>= (g-ref grid y x*) v))
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1)
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(for/sum ([y* (in-range (sub1 y) -1 -1)] #:final (>= (g-ref grid y* x) v))
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1)
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(for/sum ([y* (in-range (add1 y) h)] #:final (>= (g-ref grid y* x) v))
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1)))
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(apply max
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(for*/list ([y (in-range h)] [x (in-range w)])
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(scenic-score y x))))
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(define (parse fname)
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(for/vector ([line (in-list (file->lines fname))])
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(for/vector ([chr (in-list (string->list (string-trim line)))])
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(- (char->integer chr) (char->integer #\0)))))
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(module+ main
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(define input (parse "inputs/8"))
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(answer 8 1 (time (part1 input)))
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(answer 8 2 (time (part2 input)))
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(displayln "meow"))
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