Based on the problem statement, your objective is to create a memory representation that includes only

the $20$ active users at any given time. To illustrate this concept, let's examine a toy example of an accesscontrol matrix provided below. In this example, there are a total of $5$ users, and we assume that only

User $1$ and User $3$ are active. Users $0,2,4,$ and $5$ are considered inactive.

Each user can have access to two resources, denoted as Read $($R$),$ Write $($W$),$ or None. An access control

matrix typically consists of rows and columns, where the first column represents the users and the

remaining columns represent the resources. If any element in the first column is zero, it indicates that

the corresponding user is inactive and does not require memory allocation. On the other hand, active

users need to be allocated memory as they require authentication to access the resources. This

authentication is represented by the values $"$R$"($Read$),"$W$"($Write$),$ or "None".

By designing a memory representation that dynamically allocates memory only for active users, you can

optimize resource usage and ensure transparent access for all users.