34 lines
790 B
Racket
34 lines
790 B
Racket
#lang curly-fn racket
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(require "scripts/aoc.rkt")
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;; solution for day 3
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(define priorities
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(string->list "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"))
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(define (part1 input)
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(for/sum ([line (in-list input)])
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(define-values [left right] (split-at line (/ (length line) 2)))
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(~>> (set-intersect left right)
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(set-first)
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(index-of priorities))))
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(define (part2 input)
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(match input
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['() 0]
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[(list* a b c rst)
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(+ (~>> (set-intersect a b c)
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(set-first)
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(index-of priorities))
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(part2 rst))]))
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(define (parse fname)
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(map string->list (file->lines fname)))
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(module+ main
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(define input (parse "inputs/3"))
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(answer 3 1 (time (part1 input)))
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(answer 3 2 (time (part2 input)))
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(displayln "meow"))
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