public long Solve(string textfile = "")
{
primes = PrimesUtil.SetUpPrimes(10000000).ToHashSet();
var maxRun = 0;
var maxRunA = 0;
var maxRunB = 0;
for (int b = 2; b < 1000; ++b)
{
if (primes.Contains(b))
{
for (int a = -999; a < 1000; ++a)
{
if (primes.Contains(1 + b + a))
{
var run = MaxPrimeRun(a, b) + 2;
if (run > maxRun)
{
maxRun = run;
maxRunA = a;
maxRunB = b;
}
}
}
}
}
return(maxRunA * maxRunB);
}
public long Solve(string textfile = "")
{
primes = PrimesUtil.SetUpPrimes(maxToCheck);
List <int> abundantNums = new List <int>(500);
bool[] sumOfTwoAbundants = new bool[maxToCheck];
FindAllAbundantNums(maxToCheck, abundantNums);
foreach (int abundantNum in abundantNums)
{
for (int i = 0; i < abundantNums.Count; ++i)
{
var sum = abundantNum + abundantNums[i];
if (sum < maxToCheck)
{
sumOfTwoAbundants[sum] = true;
}
}
}
var totalNonAbundants = 0;
for (int i = 1; i < maxToCheck; ++i)
{
if (!sumOfTwoAbundants[i])
{
totalNonAbundants += i;
}
}
return(totalNonAbundants);
}