design and analysis of algorithms - kent state...
TRANSCRIPT
Design and Analysis of Algorithms
This Class
Website and Contact
Website
I www.cs.kent.edu/∼aleitert/fall15/
I Important information
I Slides
I Announcements
Feedback
I First time teaching this class.
I Feedback is appreciated.
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Primary Textbook
A L G O R I T H M SI N T R O D U C T I O N T O
T H I R D E D I T I O N
T H O M A S H.
C H A R L E S E.
R O N A L D L .
C L I F F O R D S T E I N
R I V E S T
L E I S E R S O N
C O R M E NIntroduction to Algorithms,by Cormen et al.3rd edition, MIT Press, 2009
Primary source for this class.
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Other Textbooks
The Algorithm Design Manual,by Steven S. Skiena2nd edition, Springer, 2008
PDF-Version available for free atSpringer Link
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Other Textbooks
ptg
Algorithms, 4th Edition,by Robert Sedgewick and Kevin Wayne4th edition, Addison-Wesley Professional, 2011
Algorithm Design: Foundations, Analysis, and InternetExamples,by Michael T. Goodrich and Roberto Tamassia, 1stedition, Wiley, 2001
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Clarification
Clarification
You do not need (to buy) a textbook. These are recommendations ifyou are looking for a textbook to study.
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Course Requirements
Exam 1 25 % Oct. 8, during classExam 2 25 % Oct. 29, during classExam 3 25 % Nov. 24, during classFinal Exam 25 % Thursday, December 17, 7:45 – 10:00 a.m.
HW (normal) 0 %HW (bonus) 10 %
(Dates may change.)
Exams
I closed book examination
I one handwritten sheet (one side) allowed
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Homework
Normal Homework
I Will not be graded.
I Good preparation for exams.
Bonus Homework
I Mostly implementation problems
I Helpful to understand details of algorithms
I Up to 10 % to your final grade.
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Office Hours
Tuesday and Thursday, 2.00 – 3.00 p.m.Room 352, Math and CS Building
“I have class during office hours”
I Send me an email. We will find some time.
I Please tell me directly when you have time to meet.
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Algorithms
Algorithm
Question
What is an algorithm?
Wikipedia
An algorithm is a self-contained step-by-step set of operations tobe performed. [...] An algorithm is an effective method that canbe expressed within a finite amount of space and time [...] forcalculating a function. Starting from an initial state and initialinput, the instructions describe a computation that [...] proceedsthrough a finite number of well-defined successive states,eventually producing “output” and terminating at a final endingstate.
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Algorithm
Question
What is an algorithm?
Wikipedia
An algorithm is a self-contained step-by-step set of operations tobe performed. [...] An algorithm is an effective method that canbe expressed within a finite amount of space and time [...] forcalculating a function. Starting from an initial state and initialinput, the instructions describe a computation that [...] proceedsthrough a finite number of well-defined successive states,eventually producing “output” and terminating at a final endingstate.
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Algorithm
Algorithm
An algorithm is a finite and well-defined set of operations which computean output for a (possible empty) input.
AlgorithmInput Output
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Properties of Algorithms
Correctness
I Will it produce the desired output?
I We will prove that our algorithms are correct.
Efficiency
I How fast is the algorithm?
I How much resources does it need?
I Is there a faster algorithm?
Having one of both properties is (usually) easy. However, having both isthe goal.
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Example
Problem
Finding doubles
You have given two integer arrays A and B. Is there an integer i which isin both arrays?
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Algorithm 1
1 For Each a ∈ A
2 For Each b ∈ B
3 If a = b Then
4 Return “Yes”
5 Return “No”
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Algorithm 2
1 Sort A and B.
2 Set i := 0 and j := 0.
3 While i < |A| and j < |B|
4 If A[i] = B[j] Then
5 Return “Yes”
6 Else If A[i] < B[j] Then
7 Set i := i + 1.
8 Else If A[i] > B[j] Then
9 Set j := j + 1.
10 Return “No”
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Question
Question
Which algorithm is better and why?
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