2 Weeks, 5 round tech interviews, I was on the campus interview process. One of the problems is Given a n-by-n matrix, each cell has a value of either 0 or 1. A cell indicates a wall if its value is 1. Give the length of the shortest path from M[0][0] to M[n-1][n-1]. You can move either up, down, left or right.

Most of them are algorithm problems.