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#lang racket
(require "../../shared/chapter1.rkt")
(require sicp)
(define expmod (expmoder (lambda (b e m x) x)))
(define (fermat-test n)
(define (try-it a)
(= (expmod a n n) a))
(try-it (+ 1 (random (- n 1)))))
(define (fast-prime? n times)
(cond
((= times 0) true)
((fermat-test n) (fast-prime? n (- times 1)))
(else false)))
(define (report-prime n t duration)
(print n)
(println " *** prime")
(println duration)
t)
(define (start-prime-test n start-time)
(if (fast-prime? n 3)
(report-prime n true (- (current-inexact-milliseconds) start-time))
false))
(define (time-prime-test n)
(start-prime-test n (current-inexact-milliseconds)))
(define (search-for-primes found n)
(cond
((> found 2) "found three primes")
((time-prime-test n) (search-for-primes (+ found 1) (+ n 2)))
(else (search-for-primes found (+ n 2)))))
(println " *** search for primes")
(search-for-primes 0 1001)
(println " *** search for primes")
(search-for-primes 0 10001)
(println " *** search for primes")
(search-for-primes 0 100001)
(println " *** search for primes")
(search-for-primes 0 1000001)
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