1. CS2006- Data Structures I Chapter 5 Linked Lists III

2. Linked Lists Types of lists: Singly-Linked: Lists with only one “pointer” per node. Doubly-Linked: Lists with two pointers per node. Multi-Linked: Lists with two or more pointers per node Circular: Last node points to the head

3. Variations of Linked Lists Circularly-Linked Lists Every node points to its successor An external pointer points to the list’s head Exercise: Write the algorithm to traverse a circular list What are the modification to be done to the original algorithm?

4. Variations of Linked Lists Circular Linked list Circular list with pointer to last node How to display all the contents in each node? List or head 20455176 head 20455176

5. Variations of Linked Lists Doubly-Linked Lists Each node has two references, one for predecessor (prev) and another for successor (next) (how to change the code?) Allows deleting without traversing the list to find the previous node Insertion is more involved than singly-linked list Special case? Head 20765145

6. Variations of Linked Lists Circular doubly-linked list Using dummy Head Head 765145 Dummy Head node

7. Doubly Linked List Implementation public class Node { private Object item; private Node next; private Node prev; public Node(Object newItem) { item = newItem; next = null; prev = null; } // end constructor public Node(Object newItem, Node nextNode, Node prevNode) { item = newItem; next = nextNode; prev = prevNode; } // end constructor

8. Doubly Linked List Implementation (2) Assume: add set and get methods for prev reference to the Node class. possibly change the insertion and deletion methods in the List class.

9. Doubly Linked List Insertion Node Insertion (add after curr): 1. Change the next pointer of the node pointed by curr 2. Change the prev pointer of the new node to point to the preceding node of curr 3. Set the Prev pointer in the node following the new node to point to the new node 4. Set the next pointer in the preceding node to point to the new node

10. Doubly Linked List Deletion Node Deletion (delete the node pointed by curr): 1. Change the next pointer of the node that precedes curr 2. Change the prev pointer of the node that follows curr to point to the preceding node of curr (cur.getPrev()). getNext ()= cur.getNext(); (cur.getNext()).getPrev()= cur.getPrev();

11. 11 Review An array-based implementation of an ADT list ______. requires less memory to store an item than a reference-based implementation is not a good choice for a small list has a variable size has items which explicitly reference the next items

12. 12 Review In a reference-based implementation of an ADT list ______. increasing the size of the list can waste storage and time less memory is required to store an item than in an array-based implementation an item explicitly references the next item the location of the item after a particular item is implied

13. 13 Review In a linear linked list, ______. the next reference of each node has the value null the last node references the first node the precede reference of the dummy head node references the last node the next reference of the last node has the value null

14. 14 Review In all circular linked lists, ______. every node references a predecessor every node references a successor the next reference of the last node has the value null each node references both its predecessor and its successor

15. 15 Review Which of the following is NOT true about all circular linked lists? every node references a successor the last node references the first node the precede reference of each node references the node that precedes it no node contains null in its next reference

16. 16 Review Which of the following is true about all doubly linked lists? each node references both its predecessor and its successor the precede reference of the last node has the value null the last node references the first node the precede reference of the first node references the last node

17. 17 Review A dummy head node ______. facilitates adding nodes at the end the linked list is used to store the first item in the linked list is the second node in the linked list is always present, even when the linked list is empty

18. Assignment 3 Write a program to manipulate the bill info Using linked List Each node contains one bill record Loop Read from file Insert into the list Print the list Prompt to the user for serial number of a bill If not found, ask for more info, to insert If found, ask if a deletion is needed

19. Structure Charts Structure chart: Bill List Prompt for input print BillsRead Bill Info Read Bill Insert Bill Into LL

20. Assignment 3 class BillNode contains Serial Number, Deno, Month, Date. class BillList contains head of LL, those methods. Class Assignment3 contains the main ()