public HashSet <Action> actions(System.Object state)
{
EightPuzzleBoard board = (EightPuzzleBoard)state;
HashSet <Action> actions = new HashSet <Action>();
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 System.Object result(System.Object s, Action 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);
}
