Answer the following questions.

a$)$ Review the contiguous implementation of the stack under Lecture $1$ in D$2$L$.$ The implementation is based on the following two instance variables:

int count;

Stack$\_$entry entry$[$maxstack$]$;

It is easy to see that methods push, pop, top and empty have a time complexity of $O(1).$ Assume that we now want to implement the same stack using the linked implementation given in "Linked List" under Lecture $1$ in D$2$L$.$ The implementation is based on the following two instance variables:

int count;

Node$(O(1))(O(1))O(1)$