/// <summary>
/// Enumerate indexes.
/// </summary>
/// Developer notes: I tried to use a pointer for cards[] too, but it does not changes the speed.
static void CombinInternal <ParamT>(int *liveCards, int liveCardsCount, int count, int[] cards, int startPos, EnumerateActionIdxDelegate <ParamT> action, ParamT param)
{
switch (count)
{
case 0:
action(cards, param);
break;
case 1:
for (int c1 = 0; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
action(cards, param);
}
break;
case 2:
for (int c1 = 1; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
for (int c2 = 0; c2 < c1; ++c2)
{
cards[startPos + 1] = liveCards[c2];
action(cards, param);
}
}
break;
case 3:
for (int c1 = 2; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
for (int c2 = 1; c2 < c1; ++c2)
{
cards[startPos + 1] = liveCards[c2];
for (int c3 = 0; c3 < c2; ++c3)
{
cards[startPos + 2] = liveCards[c3];
action(cards, param);
}
}
}
break;
case 4:
for (int c1 = 3; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
for (int c2 = 2; c2 < c1; ++c2)
{
cards[startPos + 1] = liveCards[c2];
for (int c3 = 1; c3 < c2; ++c3)
{
cards[startPos + 2] = liveCards[c3];
for (int c4 = 0; c4 < c3; ++c4)
{
cards[startPos + 3] = liveCards[c4];
action(cards, param);
}
}
}
}
break;
case 5:
for (int c1 = 4; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
for (int c2 = 3; c2 < c1; ++c2)
{
cards[startPos + 1] = liveCards[c2];
for (int c3 = 2; c3 < c2; ++c3)
{
cards[startPos + 2] = liveCards[c3];
for (int c4 = 1; c4 < c3; ++c4)
{
cards[startPos + 3] = liveCards[c4];
for (int c5 = 0; c5 < c4; ++c5)
{
cards[startPos + 4] = liveCards[c5];
action(cards, param);
}
}
}
}
}
break;
default:
for (int c1 = count - 1; c1 < liveCardsCount; ++c1)
{
cards[startPos] = liveCards[c1];
for (int c2 = count - 2; c2 < c1; ++c2)
{
cards[startPos + 1] = liveCards[c2];
for (int c3 = count - 3; c3 < c2; ++c3)
{
cards[startPos + 2] = liveCards[c3];
for (int c4 = count - 4; c4 < c3; ++c4)
{
cards[startPos + 3] = liveCards[c4];
for (int c5 = count - 5; c5 < c4; ++c5)
{
cards[startPos + 4] = liveCards[c5];
CombinInternal(liveCards, c5, count - 5, cards, startPos + 5, action, param);
}
}
}
}
}
break;
}
}
/// <summary>
/// Combin all possible combinations of cards and calls an action for each combination.
/// </summary>
/// <param name="cards">Array to put the cards to.</param>
/// <param name="startPos">Starting position in the cards array.</param>
/// <param name="deadCards">Dead cards. If some shared cards are necessary, put it manually to both cards and deadCards.</param>
public static void Combin <ParamT>(DeckDescriptor deckDescr, int count, int[] cards, int startPos, int[] deadCards, int deadCardsCount, EnumerateActionIdxDelegate <ParamT> action, ParamT param)
{
int[] deckCopy = deckDescr.FullDeckIndexes.ShallowCopy();
for (int i = 0; i < deadCardsCount; ++i)
{
deckCopy[deadCards[i]] = -1;
}
int liveCardsLength = deckCopy.Length - deadCardsCount;
int *liveCards = stackalloc int[liveCardsLength];
int cnt = 0;
for (int i1 = 0; i1 < deckCopy.Length; ++i1)
{
if (deckCopy[i1] >= 0)
{
liveCards[cnt++] = deckCopy[i1];
}
}
Debug.Assert(cnt == liveCardsLength);
CombinInternal(liveCards, liveCardsLength, count, cards, startPos, action, param);
}
