I originally plan to use this section to review some array knowledge. but after going through the whole section, I found it frustrating, I think they are not organized very well:

• Questions are hard for beginner
• Clear gap between context and quetions,

For example, the intro and those chapters looks like targeting for people who are new to array. But afterwards questions are suddenly put into the level where two pointers, in-place operations, sliding windows techinique are required. However, those techniques are barely covered in these chapters. There is a gap that need to fill it by student themselves if they are beginner.

Anyway, I still want to thank the writers for generating this. Stuff are specific and clearly I can see they think a lot on this project from those VCD metaphor, trying to make it easy-understand. But the questions are just not friendly enough for beginner. They may get frustrating.