public PrimeSieve2(long upTo)
{
primes = new GrowableArray<bool>(upTo);
primes.Set(0, true);
primes.Set(1, true);
PopulateSieveFrom(primes);
}
public void TestArrayAccess()
{
int sz = 100;
GrowableArray<int> ga = new GrowableArray<int>(sz);
for(int i = 0; i < 2 * sz; ++i)
{
ga.Set(i, 13*i);
Assert.AreEqual(i < sz ? sz : 2 * sz, ga.LongLength);
}
for(int i = 0; i < 2 * sz; ++i)
{
Assert.AreEqual(i*13, ga.Get(i));
}
}
private static void PopulateSieveFrom(GrowableArray<bool> sieve, long from = 2)
{
long upTo = (long)Math.Sqrt(sieve.LongLength) + 1;
for (long i = 2; i < upTo; i++)
{
if (!sieve.Get(i))
{
var k = (i < from) ? FirstK(i, from) : 2 * i;
while (k < sieve.LongLength)
{
sieve.Set(k,true);
k += i;
}
}
}
}