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;
}