CMPU-102 Spring, 2020
Pete Lemieszewski
Remote Lab 3

For This lab, we will implement the specifications for the set ADT (Abstract
Data Type). Start by using the linked list implementation from Remote Lab 2. 
There are two additional implementations for you to complete, one for extra 
credit. The Set collection only contains unique elements, or is empty.
The ADT specifications for a set are defined in the ISet interface and are 
included here:

1. add:      add an element to the set, if possible.
             returns:
		     true, if the element is added
		     false, if the element could not be added
2. contains: determines whether a given element is in the set.
			 returns:
			 true, if the element exists in the set
			 false, if the element does not exist in the set
3. remove:	 removes an element from the set
			 returns:
			 true, if the element exists, and is removed from the set
			 false, if the element does not exist in the set
4. getSize:  provides the number of elements in the set
			 returns:
			 the number of elements in the set
5. toString: provides a String representation of the elements in the set
			 returns:
			 String object that can be used to display the elements in the set.
			 
The classes for the various implementations of this interface:

1. SetMyLinkedList: uses the list class you created during the the last lab as
   the underlying data structure. Be sure to copy your own list code over to the
   MyLinkedList class.

2. SetJavaLinkedList: uses the java.util.LinkedList class. The following
   java.util.LinkedList methods are recommended:

   - add(E elem): append elem to end of list. Always returns true.
   - add(int idx, E elem): insert elem at index idx.
   - remove(int idx): removes and returns element at index idx.
   - get(int idx): returns element at index idx.
   - indexOf(Object o): returns index of object o, if it is present in the list,
     or -1 otherwise. The Object.equals() method is used for the comparison.
   - size(): returns the length of the list.
   
3. SetJavaArrayList: for extra credit! implement using the java.util.ArrayList class. 
   ArrayList supports the same basic methods as java.util.LinkedList.
   
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Benchmarking

Class "SetTest" is provided for you to test and benchmark your code with. For
each of the different implementations, it creates an empty set, adds 50000
elements, tests their existence and then removes them. Elements are tested for
existence and removed in a random order. Assert statements are used to test
correctness. Furthermore, this class also times each of the implementations to
show you how their performance compares.

Analyze the code until you understand what it does and then run the main method.
If your code is correct, main should not throw any AssertionErrors and should
print out timing information for each of the different set implementations.

Note: since assertions are used to test correctness, be sure to use the -ea flag
to enable assertions if running java outside of BlueJ.

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For extra credit: (I'll accept extra credit assignments through Friday)

Use the array-based list code we saw in class to create your own array-based
set implementation and test it against the others.

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Upon completion

Once the program is working as specified, please contact a coach or professor to
check your work and give you credit. Finally, compress your source files using 
zip, tar or another of your favorite compression utilities and submit them 
through Moodle. 
(Yes, I have it set up! https://moodle.vassar.edu/mod/assign/view.php?id=618632)