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solved 47 in racket, ugly code

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Lowl3v3l 2017-07-11 16:56:15 +02:00
parent 65b6786569
commit 8564d3de28
1 changed files with 22 additions and 0 deletions
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#lang racket
(require math/number-theory)
(define (primefactors x)
(if (prime? x)
(list x)
(for/or ((i (cons 2 (range 3 (+ 1 (ceiling (sqrt x))) 2)))
#:when (prime? i)
#:when (zero? (remainder x i)))
(cons i (primefactors (quotient x i))))))
(define (recur x)
(if (and
(equal? (length (remove-duplicates (primefactors x))) 4)
(equal? (length (remove-duplicates (primefactors (+ x 1)))) 4)
(equal? (length (remove-duplicates (primefactors (+ x 2)))) 4)
(equal? (length (remove-duplicates (primefactors (+ x 3)))) 4))
x
(recur (+ x 1))))
(recur 2)