public static string Problem3()
{
Console.WriteLine("\n\t3) What is the largest prime factor of the number 600,851,475,143?");
int diviser = 2;
// This number will be divided several times until it cannot be divided by numbers other than 1 and itself,
// which means we have found the biggest prime factor of the initial value.
long numberToBeDivided = 600851475143;
int initialValueSqrt = (int)Math.Sqrt(numberToBeDivided);// A prime factor of a number cannot be larger that the number's square root.
for (int i = 0; i < initialValueSqrt; i++)
{
// The numberToBeDivided is divided by the same diviser for as long as the number is divisible by that specific diviser.
while (numberToBeDivided % diviser == 0)
{
numberToBeDivided /= diviser;
}
if (MathyHelper.IsPrime(numberToBeDivided))
{
break;
}
// If the numberToBeDivided is not divisable by the current diviser anymore but it is not a prime number, we move onto the next diviser.
diviser++;
}
return(numberToBeDivided.ToString());
}
public static string Problem7()
{
Console.WriteLine("\n\t7) What is the 10,001st prime number?");
long number = 3;
int counter = 1; // 2 is already counted.
while (counter != 10001)
{
if (MathyHelper.IsPrime(number))
{
counter++;
}
number += 2;
}
return((number - 2).ToString());
}
