Created
November 6, 2016 20:50
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problem #3 in projecteuler to find the largest prime factor using sieve segmentation and scala streams
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| def sieve(s: Stream[Long]): Stream[Long] = s.head #:: sieve(s.tail filter (_ % s.head != 0)) | |
| def from(n: Long): Stream[Long] = n #:: from(n + 1) | |
| def primes = sieve(from(2)) | |
| def largest(x: Long, p: Stream[Long]):Long = { | |
| if (x <= p.head) x | |
| else if (x % p.head == 0) largest(x / p.head, p) | |
| else largest(x,p.tail) | |
| } | |
| largest(600851475143L, primes) |
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