Notes

Outline

Linked Lists Implementation


	Operations for Lists.
	Implementation of Linked Lists.
	Double Linked Lists.

Data structures


	(informally:)
	By size:
		Static (e.g. arrays)
		Dynamic (e.g. vectors)

	By ordering:
		Last In First Out (LIFO)
		First In First Out (FIFO)
		Priority

Data Structures



	Types of dynamic generic data structures are:

				Stacks
				Queues
				Lists
				Trees

What is Dynamic Memory?


	Memory which is allocated and de-allocated during the execution of the program.
	Types:
		data in run-time stack
		dynamic data in the heap

List Operations


	Go to a position in the list.
	Insert an item at a position in the list.
	Delete an item from a position in the list.
	Retrieve an item from a position.
	Replace an item at a position.
	Traverse a list.

Comparison


	Linked Storage
		Unknown list size.
		Flexibility is needed.

	Contiguous Storage
		Known list size.
		Few insertions and deletions are made within the list.
		Random access

Linked List

Constructor for the NodeClass


	Public IntNode (int initial Data, IntNode initial Link)
	{
	data = initialData;
	link = initialLink:
	}

Set Position


	check if position is within range
	start with address of head node
	set count to 0
	while count is less than position
		follow link to next node
		increment count
	return address of current node

Set Position

Set Position

Set Position

Set Position

Find a Position in a Linked List


	public static IntNode listPosition (IntNode head, int position)
	{
	IntNode cursor;
	int i;
	if (position <=0)
	throw new IllegalArgumentException (“position is invalid”);
	cursor = head;
	for (i=1; (i < position) && (cursor != null); i++)
	cursor = cursor.link;
	return cursor;
	}

Insert

Insert

Slide 17

Slide 18

Inserting – New List

Inserting – New List

Inserting – Start of List

Inserting – Start of List

Inserting – Start of List

Inserting – Inside the List

Inserting – Inside the List

Inserting – Inside the List

Delete

Slide 28

Slide 29

Slide 30

Deleting – 1^st Node

Deleting – 1^st Node

Deleting – 1^st Node

Deleting – Middle Node

Deleting – Middle Node

Deleting – Middle Node

Deleting a Node that is not at the Head


	Activate the following method:
	selection.removeNodeAfter( );
	where selection is a reference to a node of a linked list.

	Implementation needs only one statement:
	link = link.link

Double Linked List Operations


	Go to a position in the list.
	Insert an item in a position in the list.
	Delete an item from a position in the list.
	Retrieve an item from a position.
	Replace an item at a position.
	Traverse a list, in both directions.

Double Linked List

Insert at end

Insert at end

Insert at end

Insert inside the list

Insert inside the list

Insert inside the list

Insert inside the list

Insert inside the list

Delete from end

Delete from end

Delete from end

Delete from inside list

Delete from inside list

Delete from inside list

Delete from inside list