/// <summary>
/// Intersects two nodes. If
/// </summary>
/// <param name="A"></param>
/// <param name="B"></param>
/// <returns></returns>
public static SetNode Intersect(SetNode A, SetNode B)
{
if (A.Type == SetNode.NodeType.OPERATOR || B.Type == SetNode.NodeType.OPERATOR)
{
return(new OperatorSet(OperatorSet.OperatorType.INTERSECTION, A, B));
}
var(goodAPieces, badAPieces) = GatherEvaluablePieces(A as Set);
var(goodBPieces, badBPieces) = GatherEvaluablePieces(B as Set);
if (goodAPieces.Count * goodBPieces.Count == 0)
{
return(new OperatorSet(OperatorSet.OperatorType.INTERSECTION, A, B));
}
var newPieces = new List <Piece>();
foreach (var goodAPiece in goodAPieces)
{
foreach (var goodBPiece in goodBPieces)
{
var piece = PieceFunctions.Intersect(goodAPiece, goodBPiece);
if (!(piece is null) && PieceFunctions.IsPieceCorrect(piece))
{
newPieces.Add(piece);
}
}
}
var union = UniteList(newPieces);
var badA = new Set {
Pieces = badAPieces
};
var badB = new Set {
Pieces = badBPieces
};
if (union.Count == 0)
{
if (badA.IsEmpty() || badB.IsEmpty())
{
return(new Set());
}
else
{
return(new OperatorSet(OperatorSet.OperatorType.INTERSECTION, badA, badB));
}
}
var united = new Set {
Pieces = union
};
if (badBPieces.Count + badAPieces.Count == 0)
{
return(united);
}
/*
* A = A1 or A2 (A1 - good, A2 - bad)
* B = B1 or B2 (B1 - good, B2 - bad)
* A & B = (A1 & B1) | (A1 & B2) | (A2 & B1) | (A2 & B2)
*/
var goodA = new Set {
Pieces = goodAPieces
};
var goodB = new Set {
Pieces = goodBPieces
};
return(OperatorSet.Or(
united, // A1 & B1
OperatorSet.Or(
OperatorSet.And( // A2 & B2
badA,
badB
),
OperatorSet.Or(
OperatorSet.And(badA, goodB), // A2 & B1
OperatorSet.And(badB, goodA) // A1 & B2
))));
}
