CS2006- Data Structures I

Chapter 5Linked Lists III

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

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?

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

20 45 51 76

head

20 45 51 76

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

20 765145

Variations of Linked Lists

Circular doubly-linked list Using dummy Head

Head

765145Dummy

Head node

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

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.

Doubly Linked List Insertion

Node Insertion (add after curr): 1. Change the next pointer of the node pointed

by curr2. Change the prev pointer of the new node to

point to the preceding node of curr3. Set the Prev pointer in the node following

the new node to point to the new node4. Set the next pointer in the preceding node to

point to the new node

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

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

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

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

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

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

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

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

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

Structure Charts

Structure chart:

Bill List

Prompt for inputprint BillsRead Bill Info

Read BillInsert Bill

Into LL

Assignment 3

class BillNode contains Serial Number, Deno, Month, Date.

class BillList contains head of LL, those methods.

Class Assignment3 contains the main ()