public string Run()
{
foreach (int prime in sieve.GetPrimes(1487))
{
int prime2 = prime + STEP;
int prime3 = prime + 2 * STEP;
if (sieve.IsPrime(prime2) && sieve.IsPrime(prime3))
{
List <int> digits1 = GetDigits(prime).ToList();
digits1.Sort();
List <int> digits2 = GetDigits(prime2).ToList();
digits2.Sort();
List <int> digits3 = GetDigits(prime3).ToList();
digits3.Sort();
bool isDesiredNumber = true;
for (int i = 0; i < digits1.Count; ++i)
{
if (digits1[i] != digits2[i] || digits2[i] != digits3[i] || digits1[i] != digits3[i])
{
isDesiredNumber = false;
break;
}
}
if (isDesiredNumber)
{
return(prime.ToString() + prime2.ToString() + prime3.ToString());
}
}
}
return(string.Empty);
}
public int Run()
{
int count = 0;
int sum = 0;
while (count < 11)
{
int suggestedPrime = searchList[0];
searchList.RemoveAt(0);
if (_sieve.IsPrime(suggestedPrime))
{
int order = 1;
// check if it is right truncatable prime
int primeCopy = suggestedPrime;
bool isTrancatablePrime = true;
while (primeCopy > 0)
{
if (!_sieve.IsPrime(primeCopy))
{
isTrancatablePrime = false;
}
primeCopy /= 10;
order *= 10;
}
if (isTrancatablePrime && suggestedPrime > 10)
{
sum += suggestedPrime;
count++;
}
// generate suggested primes by adding from the left
for (int i = 0; i < appends.Length; ++i)
{
searchList.Add(order * appends[i] + suggestedPrime);
}
}
}
return(sum);
}
/*public void CheckPermutationPrime(int prime)
* {
* int[] digits = GetDigits(prime).ToArray();
* List<int> perm = new List<int>();
* foreach (int permutation in GetPermutations(digits))
* {
* if (!sieve.IsPrime(permutation)) return;
*
* _checkedPrimes.Add(permutation);
* perm.Add(permutation);
* }
* perm.ForEach(circularPrime => _circularPrimes.Add(circularPrime));
* }*/
public void CheckCircularPrime(int prime)
{
int length = prime.ToString().Length;
List <int> shifts = new List <int>();
int count = 1;
_checkedPrimes.Add(prime);
shifts.Add(prime);
while (count++ < length)
{
prime = prime / 10 + (prime % 10) * (int)Math.Pow(10, length - 1);
if (!sieve.IsPrime(prime))
{
return;
}
_checkedPrimes.Add(prime);
shifts.Add(prime);
}
shifts.ForEach(circularPrime => _circularPrimes.Add(circularPrime));
}
public int Run(int maxA, int maxB)
{
ESieve sieve = new ESieve(87400);
int maxN = -1, coeffProduct = -1;
for (int a = -1000; a <= maxA; ++a)
{
for (int b = -1000; b <= maxB; ++b)
{
int n = 0;
while (sieve.IsPrime(n * n + a * n + b))
{
n++;
}
if (n > maxN)
{
maxN = n;
coeffProduct = a * b;
}
}
}
return(coeffProduct);
}