public void change(int x, int y, char f){
		Point position = new Point(x, y);
		
		if(f==Constants.ROBOT) {
			
			if(getPoint(x,y)==Constants.DIAMOND)
				nDiam--;
			if(getPoint(x,y)==Constants.ROCK){

				if(x > robotPos.x){
					
					if(((x+1) <= Xmax) && getPoint(x+1,y)==Constants.EMPTY)
						map.put(new Point(x+1,y), Constants.ROCK);
				}
				if(x < robotPos.x){

					if(((x-1) > 1) && getPoint(x-1,y)==Constants.EMPTY)
						map.put(new Point(x-1,y), Constants.ROCK);
				}
			}
			robotPos = position;

		}
		map.put(position, f);
		
	}