>>>>
>>>>That's a good idea and a good algorithm. I felt so stupid, after my colleague explained this solution to me. Hovewer, this is not the best algorithm, though a very good one. People, who gave this solution, passed this interview successfully.
>>>
>>>Let me know when you find out the best one.
>>
>>Steve solved it. I was thinking in the same direction...
>
>Did he? Why did they give you two balls?

Because one ball is not enough :)