36 lines
844 B
Racket
36 lines
844 B
Racket
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(define (prime-numbers amount from)
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(if (= amount 0)
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'()
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(if (prime? from)
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(cons from (prime-numbers (- amount 1) (+ from 1)))
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(prime-numbers amount (+ from 1)))))
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(define (divisors n from)
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(if (> from n)
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'()
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(if (= (remainder n from) 0)
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(cons from (divisors n (+ from 1)))
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(divisors n (+ from 1)))))
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(define (prime? number)
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(equal? (divisors number 1) (list 1 number)))
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(define (square x) (* x x))
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(define (squares list-of-numbers)
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(if (eq? list-of-numbers '())
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'()
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(cons (square (first list-of-numbers)) (squares (rest of numbers)))))
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(define (map f list)
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(if (eq? list '())
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'()
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(cons (f (first list)) (plural f (rest list)))))
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(define (sum numbers)
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(if (eq? numbers '())
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0
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(+ (first numbers) (sum (rest numbers)))))
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;; (sum (map square (prime-numbers 7 1)))
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