Chapter 2: Getting Started

@laurocaetano, @rmascarenhas, @andrielfn and @rcillo After a lot of effort on this chapter I tried my best to solve exercises and problems, but couldn't finish all of them.
I see. I think the invariant you stated at that comment seems more accurate for me :+1: 

> Wouldn't the loop invariant be: v is not included in subarray A[1..j-1]. It is valid for initialization since j=1, the subarray has no elements, so v can't be in it.