protected double getManhatanHeuristicCost(double x, double y, double gx, double gy, double dFactor) {
        double dx = Math.abs(x - gx);
        double dy = Math.abs(y - gy);
        return dFactor * (dx + dy);
    }
protected double getManhatanHeuristicCost(double x, double y, double gx, double gy, double dFactor) {
        double dx = Math.abs(x - gx);
        double dy = Math.abs(y - gy);
        return dFactor * (dx + dy);
    }
protected double getManhatanHeuristicCost ( double x , double y , double gx , double gy , double dFactor ) { double dx = Math . abs ( x - gx ) ; double dy = Math . abs ( y - gy ) ; return dFactor * ( dx + dy ) ; }
obtains from http://theory.stanford.edu/~amitp/GameProgramming/Heuristics.html
obtains from http : // theory . stanford . edu / ~amitp / GameProgramming / Heuristics . html