public void GetPrimeFactors_Returns_Enumerator_To_Prime_Factors_In_Exponential_Form()
{
var expectedPrimeFactors = new[]
{
new Exponent(2, 1),
new Exponent(5, 2),
new Exponent(17, 1),
};
PrimeMath.GetPrimeFactors(850).Should().BeEquivalentTo(expectedPrimeFactors);
}
/// <summary>
/// Run solution for problem 47.
/// </summary>
/// <param name="consecutiveNumbersTarget">
/// Target of consecutive numbers that meets <paramref name="distinctPrimeFactorCount"/>.
/// </param>
/// <param name="distinctPrimeFactorCount">Number of district prime factors.</param>
/// <returns>
/// First number in <paramref name="consecutiveNumbersTarget"/> that is made up of
/// <paramref name="distinctPrimeFactorCount"/>.
/// </returns>
public static int Run(int consecutiveNumbersTarget, int distinctPrimeFactorCount)
{
var previousMatchedNumber = 0;
var consecutiveNumberCount = 0;
for (var i = 0; consecutiveNumberCount < consecutiveNumbersTarget; i += 1)
{
var primeFactors = PrimeMath.GetPrimeFactors(i);
if (primeFactors.Count() == distinctPrimeFactorCount &&
(previousMatchedNumber == 0 || previousMatchedNumber == i - 1))
{
previousMatchedNumber = i;
consecutiveNumberCount += 1;
}
else if (consecutiveNumberCount != 0)
{
previousMatchedNumber = 0;
consecutiveNumberCount = 0;
}
}
return(previousMatchedNumber - consecutiveNumbersTarget + 1);
}
/// <summary>
/// Run solution for problem 3.
/// </summary>
/// <param name="number">Input number.</param>
/// <returns>Largest prime factor of <paramref name="number"/>.</returns>
public static int Run(int number)
{
var primeFactors = PrimeMath.GetPrimeFactors(number);
return(primeFactors.ToArray()[^ 1].BaseValue);