Queue
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The document outlines the course on data structures and algorithms, focusing on queues as a first-in, first-out (FIFO) data structure. It details the operations performed on queues, their applications in computing, and provides a conceptual view along with implementation examples. Additionally, quiz questions are included to test comprehension of the material presented.
Queue
- 1. IT 4043 Data Structures and Algorithms Budditha Hettige Department of Computer Science 1 Queue 5
- 2. Course Outline • Introduction to DSA • Abstract Data Types (ADT) • List operation using arrays • Stacks •Queues • Recursion • Link List • Sorting • Searching • Algorithms Analysis 2
- 3. 3 Objectives • Examine queue processing • Define a queue abstract data type • Demonstrate how a queue can be used to solve problems
- 4. 4
- 5. 4 Queue • Queue: a collection whose elements are added at one end (the rear or tail of the queue) and removed from the other end (the front or head of the queue) • A queue is a FIFO (first in, first out) data structure • Any waiting line is a queue: –The check-out line at a grocery store –The cars at a stop light –An assembly line
- 6. Conceptual View of a Queue Front of queue Rear of queue 5
- 7. Conceptual View of a Queue Front of queue Adding an element The new element is added to the rear of the queue 5
- 8. Removing an element New front element of queue The element is removed from the front of the queue Conceptual View of a Queue 6
- 9. 9 Uses of Queues in Computing • Printer queue • Keyboard input buffer • GUI event queue (click on buttons, menu items) • To encode messages • For any kind of problem involving FIFO data
- 10. 10 Operations on a Queue Operation Description remove Removes an element from the front of the queue insert Adds an element to the rear of the queue isFull Determines whether the queue is full isEmpty Determines whether the queue is empty
- 11. Implementation of a Queue 11
- 12. 12 An Array Implementation of a Queue
- 13. 13 An Array Implementation of a Queue Before After
- 14. 14 An Array Implementation of a Queue
- 15. 15 An Array Implementation of a Queue
- 16. Summary • Queue: a collection whose elements are added at one end and removed from the other end • A queue is a FIFO (first in, first out) data structure • Queue Implementation (Java) 16
- 17. Questions 1. Specify 3 usages of Queues in Computing. 2. Identify which of the following is/are true? In each case justify your answer. a. Web browsers use queues to retrieve data b. In the front fix array bases queue implementation, remove operation is less efficient than insert 17
- 18. Thank you! 18