|
public queenExistsAt ( |
||
| l | ||
| return | bool | |
//
// START - Interface FitnessFunction
public double getValue(String individual)
{
double fitness = 0;
NQueensBoard board = getBoardForIndividual(individual);
int boardSize = board.getSize();
// Calculate the number of non-attacking pairs of queens (refer to AIMA
// page 117).
List <XYLocation> qPositions = board.getQueenPositions();
for (int fromX = 0; fromX < (boardSize - 1); fromX++)
{
for (int toX = fromX + 1; toX < boardSize; toX++)
{
int fromY = qPositions.get(fromX).getYCoOrdinate();
bool nonAttackingPair = true;
// Check right beside
int toY = fromY;
if (board.queenExistsAt(new XYLocation(toX, toY)))
{
nonAttackingPair = false;
}
// Check right and above
toY = fromY - (toX - fromX);
if (toY >= 0)
{
if (board.queenExistsAt(new XYLocation(toX, toY)))
{
nonAttackingPair = false;
}
}
// Check right and below
toY = fromY + (toX - fromX);
if (toY < boardSize)
{
if (board.queenExistsAt(new XYLocation(toX, toY)))
{
nonAttackingPair = false;
}
}
if (nonAttackingPair)
{
fitness += 1.0;
}
}
}
return(fitness);
}
public HashSet <Action> actions(Object state)
{
HashSet <Action> actions = new LinkedHashSet <Action>();
NQueensBoard board = (NQueensBoard)state;
for (int i = 0; i < board.getSize(); i++)
{
for (int j = 0; j < board.getSize(); j++)
{
XYLocation loc = new XYLocation(i, j);
if (!board.queenExistsAt(loc))
{
actions
.Add(new QueenAction(QueenAction.MOVE_QUEEN,
loc));
}
}
}
return(actions);
}
public override bool Equals(Object o)
{
if (this == o)
{
return(true);
}
if ((o == null) || (this.getClass() != o.getClass()))
{
return(false);
}
NQueensBoard aBoard = (NQueensBoard)o;
bool retVal = true;
List <XYLocation> locs = getQueenPositions();
foreach (XYLocation loc in locs)
{
if (!(aBoard.queenExistsAt(loc)))
{
retVal = false;
}
}
return(retVal);
}
