public ISet<IAction> Actions(object state)
{
EightPuzzleBoard board = (EightPuzzleBoard) state;
var actions = new HashedSet<IAction>();
if (board.CanMoveGap(EightPuzzleBoard.Up)) {
actions.Add(EightPuzzleBoard.Up);
}
if (board.CanMoveGap(EightPuzzleBoard.Down)) {
actions.Add(EightPuzzleBoard.Down);
}
if (board.CanMoveGap(EightPuzzleBoard.Left))
{
actions.Add(EightPuzzleBoard.Left);
}
if (board.CanMoveGap(EightPuzzleBoard.Right))
{
actions.Add(EightPuzzleBoard.Right);
}
return actions;
}
public object Result(object s, IAction a)
{
EightPuzzleBoard board = (EightPuzzleBoard) s;
if (EightPuzzleBoard.Up.Equals(a)
&& board.CanMoveGap(EightPuzzleBoard.Up))
{
EightPuzzleBoard newBoard = new EightPuzzleBoard(board);
newBoard.MoveGapUp();
return newBoard;
}
else if (EightPuzzleBoard.Down.Equals(a)
&& board.CanMoveGap(EightPuzzleBoard.Down))
{
EightPuzzleBoard newBoard = new EightPuzzleBoard(board);
newBoard.MoveGapDown();
return newBoard;
}
else if (EightPuzzleBoard.Left.Equals(a)
&& board.CanMoveGap(EightPuzzleBoard.Left))
{
EightPuzzleBoard newBoard = new EightPuzzleBoard(board);
newBoard.MoveGapLeft();
return newBoard;
}
else if (EightPuzzleBoard.Right.Equals(a)
&& board.CanMoveGap(EightPuzzleBoard.Right))
{
EightPuzzleBoard newBoard = new EightPuzzleBoard(board);
newBoard.MoveGapRight();
return newBoard;
}
// The Action is not understood or is a NoOp
// the result will be the current state.
return s;
}