public State CheckNextState(Piece piece, int x, int y, int xDir, int yDir, bool swap, IList <Piece> pieces)
{
if (piece.CheckCanPlace(_grid, x, y, xDir, yDir, swap))
{
//final state
if (pieces.Count == 0)
{
return(this);
}
piece.Place(_grid, x, y, xDir, yDir, swap);
if (!IsPossibleGrid(_grid) || _optimizer.IsKnownState(_grid))
{
piece.Reset(_grid, x, y, xDir, yDir, swap);
return(null);
}
_optimizer.SetKnownState(_grid);
var candidate = new State(pieces, _grid, _optimizer);
var candidateState = candidate.GetWinningState();
if (candidateState != null)
{
return(candidateState);
}
piece.Reset(_grid, x, y, xDir, yDir, swap);
}
return(null);
}