public static long[] GetPrimeFactors(this long value, IPrimeProvider provider, bool makeDistinct = false)
{
var factors = new List <long>(4);
foreach (var prime in provider.GetPrimes())
{
var primeWasAdded = false;
while (prime.Divides(value))
{
if (!(primeWasAdded && makeDistinct))
{
primeWasAdded = true;
factors.Add(prime);
}
value /= prime;
}
if (value == 1)
{
break;
}
}
return(factors.ToArray());
}
public PrimalityAlgorithm(IPrimeProvider provider, long greatestChecked)
{
_primes = provider.GetPrimes();
_greatestChecked = greatestChecked;
}
// ~ 3000 ms
private long SlowSolve(IPrimeProvider provider)
{
return(FindTheSmallestOfFourConsecutive(10.Power(6), number => number.GetUniquePrimeFactors(provider).Length));
}
public static long[] GetUniquePrimeFactors(this long value, IPrimeProvider provider) => value.GetPrimeFactors(provider, true);
