public override string GetAnswer()
{
// The sum of the primes up to 3943 = 1,001,604. No need to go higher.
var primes = PrimeUtilities.GeneratePrimesUpToN(3943);
// 547 primes under 3943.
for (int length = 547; length > 0; --length)
{
for (int offset = 0; offset <= primes.Count - length; ++offset)
{
int sum = 0;
for (int i = 0; i < length; ++i)
{
sum += primes[offset + i];
}
if (_primeService.IsPrime(sum))
{
return(sum.ToString());
}
}
}
return(null);
}
public override string GetAnswer()
{
// Eight and nine digit numbers that are pandigital will always be divisible by 3, so we will look at 7 digit primes.
const int limit = 7654321;
List <int> primes = PrimeUtilities.GeneratePrimesUpToN(limit);
for (int i = primes.Count - 1; i >= 0; --i)
{
if (IsPandigital(primes[i].ToString()))
{
return(primes[i].ToString());
}
}
return(null);
}
