2020-12-05 06:20:23 +00:00
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#lang racket
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2020-12-05 06:37:36 +00:00
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(require racket/set
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"../lib.rkt")
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2020-12-05 06:20:23 +00:00
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2020-12-05 06:37:36 +00:00
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(define (string->seat str)
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(string->number (string-append "#b" (regexp-replaces str '([#rx"F" "0"] [#rx"B" "1"] [#rx"L" "0"] [#rx"R" "1"])))))
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2020-12-05 06:20:23 +00:00
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2020-12-05 06:37:36 +00:00
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(define input (map string->seat (problem-input 5)))
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2020-12-05 06:20:23 +00:00
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2020-12-05 06:37:36 +00:00
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(define-values (part1 part2)
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2020-12-06 06:00:08 +00:00
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(let* ([minimum ($ min input)]
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[maximum ($ max input)]
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2020-12-05 06:37:36 +00:00
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[seats (list->set (range minimum (add1 maximum)))]
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[filled (list->set input)])
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(values maximum (set-first (set-subtract seats filled)))))
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2020-12-05 06:20:23 +00:00
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(show-solution part1 part2)
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