Asymptotically faster solution for 17.23 (Max Square Matrix)

[Qualtagh]

Hello!
The book is a real masterpiece. It helped me to understand a lot of algorithmic techniques. Inspired by it, I tried to continue improving some algorithms staying in the same vein of interview format - the solution should be short, simple to understand, readable and limited to using previously explained algorithms/data structures.
I hope it may help somebody by giving some ideas.

The commit contains:

• an implementation of an alternative algorithm with better asymptotics for a task 17.23 - O(N² * log N)
• (kind of) unit tests
• and a markdown file with thorough explanation of the approach. You can view it here.