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56 lines
2.2 KiB
Racket
56 lines
2.2 KiB
Racket
8 years ago
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#lang br/quicklang
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(require racket/string)
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(module+ reader (provide read-syntax))
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(define (read-syntax path port)
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(strip-bindings
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#`(module mod "day09.rkt"
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#,@(for/list ([str (in-lines port)]
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#:when (not (equal? str "")))
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`(solve ,(string-trim str))))))
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(provide solve #%module-begin)
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(define (solve str)
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(for-each displayln
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(let (#;[decomp-result (decomp str)]
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[decomp2-result (decomp2 str)])
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(list #;decomp-result #;(string-length decomp-result)
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decomp2-result))))
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(define (decomp str)
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(define p (open-input-string str))
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(define decompressor-pat "\\((\\d+)x(\\d+)\\)")
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(let loop ([bstrs empty][decompressor #f])
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(define cur-pat (if decompressor
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(pregexp (format ".{~a}" (car decompressor)))
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(pregexp (format "~a|." decompressor-pat))))
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(define match (let ([result (regexp-try-match cur-pat p)])
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(and result (car result))))
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(cond
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[(not match) (string-append* (map ~a (reverse (flatten bstrs))))]
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[decompressor (loop (cons (make-list (cadr decompressor) match) bstrs) #f)]
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[else
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(define maybe-decompressor (regexp-match (pregexp decompressor-pat) match))
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(if maybe-decompressor
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(loop bstrs (map (compose1 string->number ~a) (cdr maybe-decompressor)))
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(loop (cons match bstrs) #f))])))
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(define (decomp2 str)
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(define p (open-input-string str))
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(define decompressor-pat "\\((\\d+)x(\\d+)\\)")
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(let loop ([sum 0][decompressor #f])
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(define cur-pat (if decompressor
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(pregexp (format ".{~a}" (car decompressor)))
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(pregexp (format "~a|." decompressor-pat))))
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(define match (let ([result (regexp-try-match cur-pat p)])
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(and result (car result))))
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(cond
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[(not match) sum]
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[decompressor (loop (+ sum (* (cadr decompressor) (decomp2 (~a match)))) #f)]
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[else
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(define maybe-decompressor (regexp-match (pregexp decompressor-pat) match))
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(if maybe-decompressor
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(loop sum (map (compose1 string->number ~a) (cdr maybe-decompressor)))
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(loop (+ sum (string-length (~a match))) #f))])))
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