//<summary>
//Code snippet by Eric Lippert from stackexchange
//</summary>
public static IEnumerable <FractionSet> SubsetSum(FractionSet fractions, FractionData target)
{
return(from subset in fractions.EnumeratePowerSet()
where General.SimplifyFraction(subset.FractionSum().numerator, subset.FractionSum().denominator) [0] == General.SimplifyFraction(target.numerator, target.denominator) [0] &&
General.SimplifyFraction(subset.FractionSum().numerator, subset.FractionSum().denominator) [1] == General.SimplifyFraction(target.numerator, target.denominator) [1]
select subset);
// return from subset in fractions.EnumeratePowerSet ()
// where subset.FractionSum ().numerator == target.numerator && subset.FractionSum ().denominator == target.denominator
// select subset;
// return from subset in fractions.EnumeratePowerSet ()
// where subset.Sum () == (target.numerator / (float)target.denominator)
// select subset;
}
//<summary>
//Algorithm by SergeyS from stackoverflow
//</summary>
public IEnumerable <FractionSet> EnumeratePowerSet()
{
int n = fractions.Count;
int powerSetCount = 1 << n;
List <FractionSet> sets = new List <FractionSet> ();
for (int setMask = 0; setMask < powerSetCount; setMask++)
{
FractionSet set = new FractionSet();
for (int i = 0; i < n; i++)
{
if ((setMask & (1 << i)) > 0)
{
set.fractions.Add(fractions [i]);
}
}
sets.Add(set);
}
return(sets);
}
