public double heuristic(Node n) {

		RoverState curr = (RoverState) n.getState();
		RoverState parent = (RoverState) n.getParent().getState();
		int dh = curr.getHeight()-parent.getHeight();

		double diffX = curr.getCoordX()-x;
		double diffY = curr.getCoordY()-y;
		double D = 1;
		double D2 = 1.41;

		double h_diagonal = min(abs(diffX), abs(diffY));
		double h_straight = abs(diffX) + abs(diffY);
		double h = D2 * h_diagonal + D * (h_straight - 2*h_diagonal);
		return h*(1+0.5*(cos(0.5)-cos(dh/20+0.5)));


 	}