/// <summary>
/// get candidate moves -
/// this list is comprehensive - it will contain all empty cells on the board
/// and sorted - good moves come first
/// the list returned may be longer than the valid cells
/// but then will have a null location at the end
/// Actual length is (BoardSize ^ 2) - number of moves already played
/// </summary>
/// <param name="board">the board to read</param>
/// <param name="lookaheadDepth">the current depth of lookahead</param>
/// <returns>the locations</returns>
public IEnumerable<Location> CandidateMoves(HexBoard board, int lookaheadDepth)
{
// No potential good moves? return them all then
if (this.goodMoves.GetCount(lookaheadDepth) == 0)
{
return board.EmptyCells();
}
int maxListLength = (board.Size * board.Size) - this.cellsPlayedCount;
// enough space for all the possible moves
Location[] result = new Location[maxListLength];
int resultIndex = 0;
// mask out the ones that have been used - intialised to false
bool[,] maskCellSelected = new bool[board.Size, board.Size];
// good moves are found first
Location[] myGoodMoves = this.goodMoves.GetGoodMoves(lookaheadDepth);
// copy in the good moves
foreach (Location goodMoveLoc in myGoodMoves)
{
if (board.GetCellAt(goodMoveLoc).IsEmpty() && (!maskCellSelected[goodMoveLoc.X, goodMoveLoc.Y]))
{
result[resultIndex] = goodMoveLoc;
resultIndex++;
maskCellSelected[goodMoveLoc.X, goodMoveLoc.Y] = true;
}
}
// copy in all moves where the cell is empty;
// and not already in by virtue of being a good move
foreach (Cell testCell in board.GetCells())
{
if (testCell.IsEmpty() && (!maskCellSelected[testCell.X, testCell.Y]))
{
result[resultIndex] = testCell.Location;
resultIndex++;
}
}
// null marker at the end
if (resultIndex < maxListLength)
{
result[resultIndex] = Location.Null;
}
return result;
}
public IEnumerable<Location> CandidateMoves(HexBoard board, int lookaheadDepth)
{
return board.EmptyCells();
}
public void EmptyCellsTest()
{
const int SmallBoardSize = 4;
const int BoardCellCount = SmallBoardSize * SmallBoardSize;
HexBoard source = new HexBoard(SmallBoardSize);
Location[] emptyCells1 = source.EmptyCells().ToArray();
Assert.IsNotNull(emptyCells1);
Assert.AreEqual(BoardCellCount, emptyCells1.Length);
source.PlayMove(2, 2, false);
Location[] emptyCells2 = source.EmptyCells().ToArray();
Assert.IsNotNull(emptyCells2);
Assert.AreEqual(BoardCellCount - 1, emptyCells2.Length);
}