Writing a programming / algorithmic book

I wanted to take on a new challenge and start writing a book about algorithms and design. The intent is to have Simplicity by Design (SD): every Chapter is a collection of 15-30 questions, followed by the solution, followed by a C++ code snippet which can be easily re-used.

So far, I have drafts for 3 chapters: bit programming, dynamic programming, and graphs. Here an example of graph code with very classical questions: implement a graph, implement bfs, implement dfs, implement topological sort, I already have code for other graph problems.  Dynamic programming has more mathematical content and I will publish an excerpt next weeks.

A number of questions:

1. Should I publish code for public review? If so, can i still use it for the book?
2. Should I publish questions for public review?

I think that this will be one of my side projects off work for the next year or so.