public bool isGoalState(Object state)
{
board = (NQueensBoard) state;
return (allQueensPlaced() && allQueenPositionsHaveZeroAttacks(board
.getQueenPositions()));
}
private NQueensBoard placeQueenAt(int row, int column,
NQueensBoard parentBoard)
{
NQueensBoard newBoard = new NQueensBoard(parentBoard.getSize());
ArrayList queenPositionsOnParentBoard = parentBoard.getQueenPositions();
queenPositionsOnParentBoard.Add(new XYLocation(row, column));
newBoard.setBoard(queenPositionsOnParentBoard);
return newBoard;
}
private NQueensBoard placeQueenAt(int row, int column,
NQueensBoard parentBoard)
{
NQueensBoard newBoard = new NQueensBoard(parentBoard.getSize());
ArrayList queenPositionsOnParentBoard = parentBoard.getQueenPositions();
queenPositionsOnParentBoard.Add(new XYLocation(row, column));
newBoard.setBoard(queenPositionsOnParentBoard);
return(newBoard);
}
public ArrayList getSuccessors(Object state)
{
ArrayList successors = new ArrayList();
NQueensBoard board = (NQueensBoard)state;
int numQueens = board.getNumberOfQueensOnBoard();
int boardSize = board.getSize();
for (int i = 0; i < boardSize; i++)
{
if (!(board.isSquareUnderAttack(new XYLocation(numQueens, i))))
{
NQueensBoard child = placeQueenAt(numQueens, i, board);
successors.Add(new Successor("placeQueenAt " + numQueens + " "
+ i, child));
}
}
return(successors);
}
public override bool Equals(Object o)
{
if (this == o)
{
return(true);
}
if ((o == null) || (this.GetType() != o.GetType()))
{
return(false);
}
NQueensBoard aBoard = (NQueensBoard)o;
bool retVal = true;
ArrayList locs = getQueenPositions();
foreach (XYLocation loc in locs)
{
if (!(aBoard.queenExistsAt(loc)))
{
retVal = false;
}
}
return(retVal);
}
public int getHeuristicValue(Object state)
{
NQueensBoard board = (NQueensBoard)state;
return(board.getSize() - board.getNumberOfQueensOnBoard());
}
public bool isGoalState(Object state)
{
board = (NQueensBoard)state;
return(allQueensPlaced() && allQueenPositionsHaveZeroAttacks(board
.getQueenPositions()));
}