Create a solution explainer?

[jdougnac]

This is my first time contributing to an open source project, so please feel free to correct me if I'm not getting the protocol for this kind of suggestions correctly.

Since the way to get to a solution is clearly defined in each functions, perhaps it'd be helpful for students to have a step by step explanation on how a solution was reached.

Of course, this would be basically the same each and every time, but it might be helpful both for people trying to solve problems and to make sure that the logic itself is working correctly.