1 lecture 14: queues lecturer: santokh singh compsci 105 ss 2005 principles of computer science
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Lecture 14: Queues
Lecturer: Santokh Singh
CompSci 105 SS 2005
Principles of Computer Science
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• Test Information on Course Web Page.
• See the “Test and Exams” Section.
• Please try not to be late for classes.
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Tail References
Beer Wine Milk
head
Textbook, pp. 186
tail What is the advantage of having a “tail”?
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Linked Lists
Inserting and Deleting Elements
Implementing the ADT List
Compared to Arrays
Passing Linked Lists as Parameters
Variations of the Linked List
Tail References
Circular Linked Lists
Dummy Head Nodes
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Circular Linked Lists
Beer Wine Milk
list(head)
Textbook, pp. 187ff
How do you get the first Node here if the external reference “list” shown above references the last Node? – pg 188.
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Linked Lists
Inserting and Deleting Elements
Implementing the ADT List
Compared to Arrays
Passing Linked Lists as Parameters
Variations of the Linked List
Tail References
Circular Linked Lists
Dummy Head Nodes
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Dummy Head Nodes
Textbook, pp. 189ff
Wine Milk
head
What is the advantage of having a Dummy Head?
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List ADT
Linked List
Array
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List ADT
Linked List
Array
SortedList ADT
Linked List
Array
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List ADT
Linked List
Array
SortedList ADT
Linked List
Array
Stack ADT
Linked List
ArrayList ADT
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Stacks
Basic ADT Operations
Application: Undo Operations
Application: Balancing Parenthesis
Array Implementation
Linked List Implementation
Stack ADT implemented with List ADT
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Undo Operations
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Undo Operations
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Stack ADT
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Stack ADT
• Push
• Pop
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Stack ADT
void createStack ( )
void isEmpty ( )
void push ( Object newItem )
Object pop ()
void popAll ()
Object peek ()
Textbook, p. 252
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Stacks
Basic ADT Operations
Application: Undo Operations
Application: Balancing Parenthesis
Array Implementation
Linked List Implementation
Stack ADT implemented with List ADT
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Balancing Parenthesis
( a { b ( ) } )
{ a [ b ( c ) d ( ) ) ] }
Textbook, pp. 254ff
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Stacks
Basic ADT Operations
Application: Undo Operations
Application: Balancing Parenthesis
Array Implementation
Linked List Implementation
Stack ADT implemented with List ADT
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Array Implementation
items: 153
2
top:
0 1 2 3
4 5 6 7
Java Code, Textbook, pp. 260ff
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Stacks
Basic ADT Operations
Application: Undo Operations
Application: Balancing Parenthesis
Array Implementation
Linked List Implementation
Stack ADT implemented with List ADT
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Linked List Implementation
1 5 3
top
Java Code, Textbook, pp. 263ff
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ADT List Implementation
Java Code, Textbook, pp. 263ff
1. 1
2. 5
3. 3
4.
5.
6.
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Queues
Basic ADT Queue Operations
"Circular" Array Implementation
Linked List Implementation
"Circular" Linked List Implementation
Queue ADT implement with List ADT
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Queue
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Queue
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Queue ADT
void createQueue ( )
void isEmpty ( )
void enqueue ( Object newItem )
Object dequeue ()
void dequeueAll ()
Object peek ()
Textbook, p. 299