Describe how to solve the Reader$-$Writers problem with semaphore. You can use the pseudocode on slides and explain how it works.

$(1)$ What are the needed semaphores and why. $[5$ points$]$

$(2)$ What are the initial values for the semaphores and why. $[5$ points$]$

$(3)$ How the code works in different scenarios, for example, when one$/$multiple writers, when one$/$multiple readers, when one$/$multiple writers and one$/$multiple readers, etc. $[10$ points$]$