Question

Can anyone give me an overview of the topic Combinatories and Discrete Probability?

Answer 1

*Combinatorics*

Answer 2

Since you are asking in Computer Science rather than in math, I am guessing you mean you need some software application of it. Here is a book that covers the topic and comes with some source code:

http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html

There are a number of others out there, but most are not free. They can be found with a search for:
https://www.google.com/search?q=Combinatorics+in+computer+science