I received an interview call from the on-campus career center. This was a screener for a second, on-campus interview in NYC. BlackRock is known to be selective, and it surely is so.

The interviewer started by asking me what my favorite subject was, and then gave me a coding problem.

I was given an N*N matrix with boolean 0s and 1s. 1s meant that you are "not stuck," and 0 meant you could not move further. After starting from a random '1' position in the matrix, the idea was to traverse the matrix until you encountered an edge with a '1'.

The problem involved using a good backtracking algorithm to go back to the starting point and find another route in case you got "stuck" while searching for a '1'.

They interviewed 13 people and put 1 or 2 guys on hold, while rejecting or not giving a reply to all the others.

I hope this helps.

They asked me to code the algorithm I proposed in 10 minutes. I asked all others who interviewed with him, and they all said he did not seem happy with the answer. I guess they have a lot of expectations.