[JanezStupar]

While I do not think that the problem is hard in a sense that if you came to me and wanted it solved for you I couldn't do it. I do think that it is a horrible interview question.

I fail to see why one would ask this kind of question and what one would take away from the answer.

How does being able to solve problem like this help make Jack Dorsey richer and more respected? How does it help Twitter users have a better experience? How does it help the interviewer assess whether this dude on the other side will make his life more bearable by not shitting all over the carpet?

I think it is mostly a form of geek bullying and intellectual mastrubation for its own sake. I have a message for the people running companies where these kinds of hiring practices are taking place. You have some insane geeks on the loose and you should catch them and lock them into the darkest dungeon as they __will__ ruin your company.

[huhtenberg]

It's a test question, duh. You struggle with it - you clearly lack field experience. It doesn't make you an idiot, it doesn't disqualify you as a programmer, it merely tests whether you have a particular basic skill or not.