/// <summary>
/// Enumerate all of the possible choice combinations of card sets on the table for use in determining
/// possible plays.
/// To this end we can remove all cards from the table that are higher value than that of the thrown
/// card as well as eliminate partial sets that sum to a value greater than that of the thrown card.
/// </summary>
/// <param name="set">The set of cards to select choices from</param>
/// <param name="target">The target card to check value against</param>
/// <returns>
/// Flag indicating if the given set of cards contains a subset of cards whose values sum to the value
/// of the target card.
/// </returns>
public static List <List <Card> > EnumerateAll(List <Card> set, Card target)
{
Debug.Assert(set != null);
set = new List <Card>(set);
set.RemoveAll(delegate(Card c) {
return((int)c > (int)target);
});
List <List <Card> > list = new List <List <Card> >();
if (set.Count > 0)
{
for (int k = 1; k <= set.Count; ++k)
{
ChoiceEnumerable <Card> enumerable = new ChoiceEnumerable <Card>(k, set.ToArray <Card>());
foreach (Card[] cards in enumerable)
{
if ((int)target == cards.Sum <Card>(a => (int)a))
{
list.Add(new List <Card>(cards));
}
}
}
}
return(list);
}
/// <summary>
/// Enumerate all of the possible choice combinations of card sets on the table for use in determining
/// if a throw is legal or not. A throw is not legal when a trick can be taken using the card. This
/// means that if there is a card of equal value on the table the throw is not legal. If there is a
/// set of cards on the table that sum to the value of the thrown card then the throw is not legal.
/// To this end we can remove all cards from the table that are higher value than that of the thrown
/// card as well as eliminate partial sets that sum to a value greater than that of the thrown card.
/// Also this method fails fast once a set is identified to meet the criteria then the method returns
/// without checking for other possible sets.
/// </summary>
/// <param name="set">The set of cards to select choices from</param>
/// <param name="target">The target card to check value against</param>
/// <returns>
/// Flag indicating if the given set of cards contains a subset of cards whose values sum to the value
/// of the target card.
/// </returns>
private static bool Enumerate(List <Card> set, Card target)
{
Debug.Assert(set != null);
set = new List <Card>(set);
// Remove all Cards of value greater than the target, combinations with those cards are impossible
set.RemoveAll(delegate(Card c) {
return((int)c > (int)target);
});
if (set.Count > 1)
{
for (int k = 2; k <= set.Count; ++k)
{
ChoiceEnumerable <Card> enumerable = new ChoiceEnumerable <Card>(k, set.ToArray <Card>());
foreach (Card[] cards in enumerable)
{
if ((int)target == cards.Sum <Card>(a => (int)a))
{
return(true);
}
}
}
}
return(false);
}
