4. (20 marks) Exercise 2.3. Design and implement a RandomQueue. This is an implementation of the Queue interface in which the remove() operation removes an element that is chosen uniformly at random among all the elements currently in the queue. (Think of a RandomQueue as a bag in which we can add elements or reach in and blindly remove some random element.) The add(x) and remove() operations in a RandomQueue should run in constant time per operation. 5. (20 marks) Exercise 3.12. Write a method, reverse(, that reverses the order of elements in a DLList. 6. (20 marks) Exercise 3.14. Design and implement a Minstack data structure that can store comparable elements and supports the stack operations push (x), pop), and size), as well as the min() operation, which returns the minimum value currently stored in the data structure. All operations should run in constant time