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deuglyfied euler3.rkt

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Lowl3v3l 2017-06-07 18:04:31 +02:00
parent eae9b67bac
commit 5b8cd633e7
1 changed files with 5 additions and 9 deletions
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3/euler3.rkt
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@ -2,13 +2,9 @@
(require math/number-theory)
(define (primes x) (filter prime? (range 2 (sqrt x))))
(define (max-prime-factor x)
(if (prime? x) x
(for/or ((i (filter prime? (range 2 (sqrt x)))))
(if (zero? (remainder x i)) (max-prime-factor (quotient x i)) #f))))
(define (primefactors x primes)
(if (prime? x)
(list x)
(if (zero? (remainder x (car primes)))
(cons (car primes) (primefactors (quotient x (car primes)) primes))
(primefactors x (cdr primes)))))
(apply max (primefactors 600851475143 (primes 600851475143)))
(max-prime-factor 600851475143)