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<lang Racket> |
<lang Racket> |
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#lang racket |
#lang racket |
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(define (encode str) |
(define (encode str) |
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(regexp-replace* #px"(.)\\1*" str |
(regexp-replace* #px"(.)\\1*" str (λ (m c) (~a (string-length m) c)))) |
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(λ (m c) (~a (string-length m) c)))) |
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(define (decode str) |
(define (decode str) |
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(regexp-replace* #px"([0-9]+)(.)" str |
(regexp-replace* #px"([0-9]+)(.)" str (λ (m n c) (make-string (string->number n) (string-ref c 0))))) |
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(λ (m n c) (make-string (string->number n) |
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(string-ref c 0))))) |
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</lang> |
</lang> |
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