public class KarelProgram extends Karel
{
    private void placeHolder(){
        //...
        for (int i = 0; i < 4; i++) {

        }
    }

    public void run()
    {
        while(frontIsClear()){
            if (ballsPresent()){
                move();
            } else{
                putBall();
                move();
            }

            //if right is only clear.
            if (rightIsClear() && leftIsBlocked()){
                putBall();
                putBall();
            }

            //if left is only clear.
            if (leftIsClear() && rightIsBlocked()){
                putBall();
                putBall();
            }

            //if both sides are clear
            if (leftIsClear() && rightIsClear()){
                putBall();
                putBall();
                putBall();
                putBall();
                putBall();
                putBall();
                putBall();
            }
        }

        if(frontIsBlocked()){
            putBall();
        }
    }
}