public static int DenominatorProductFractions()
{
var(multNumerator, multDenominator) = (1, 1);
for (int numerator = 10; numerator < 100; numerator++)
{
var nLeft = numerator % 10;
var nRight = numerator / 10;
for (int denominator = numerator + 1; denominator < 100; denominator++)
{
if (numerator % 10 == 0 && denominator % 10 == 0)
{
continue;
}
var fraction = numerator / (double)denominator;
var dLeft = denominator % 10;
var dRight = denominator / 10;
int a = -1, b = -1;
if (nLeft == dLeft)
{
(a, b) = (nRight, dRight);
}
else if (nLeft == dRight)
{
(a, b) = (nRight, dLeft);
}
else if (nRight == dLeft)
{
(a, b) = (nLeft, dRight);
}
else if (nRight == dRight)
{
(a, b) = (nLeft, dLeft);
}
if (a < b && fraction == a / (double)b)
{
multNumerator *= a;
multDenominator *= b;
}
}
}
return((int)Divisors.LowestCommonTerms(multNumerator, multDenominator).denominator);
}