Improved version of Testing for primality
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| (define (smallest-divisor n) | |
| (find-divisor n 2)) | |
| (define (find-divisor n test-divisor) | |
| (cond | |
| ((> (square test-divisor) n) | |
| n) | |
| ((divides? test-divisor n) | |
| test-divisor) | |
| (else | |
| (if | |
| (= 2 test-divisor) | |
| (find-divisor n (+ test-divisor 1)) | |
| (find-divisor n (+ test-divisor 2)))))) | |
| (define (divides? a b) | |
| (= (remainder b a) 0)) | |
| (define (prime? n) | |
| (= n (smallest-divisor n))) |
by