Social Network - Company-specific OAs / Twitter OA

In a social media website (which is probably Twitter, if you are wondering), there are a total of n users. Each user can follow any number of other users. Let f be a matrix of relationship between these users, where f[i][j] is either 0 or 1. A 1 indicates that person i (starting from 0) is following person j, while 0 means otherwise.

This is a companion discussion topic for the original entry at