Chapter 2: Introduction to Problem Solving

8/11/2019 Chapter 2: Introduction to Problem Solving

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TOPIC 2:INTRODUCTION TO PROBLEM

SOLVING USING COMPUTER

CSC118 Fundamental of Algorithm Development


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Objective overview

At the end of this chapter, student should beable to:

Describe typical Real World ProblemSolving Define what is Algorithm

Represent Algorithm and Logical Thinking


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Contents

1. What is problem?2. Types of problem

3. Typical Real World Problems Solving4. Algorithm

1. What is Algorithm?

2. History of Algorithm3. Algorithm and logical thinking4. Problem Solving using different algorithms
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1. What is problem?

A problem , can be caused for different reasons,and usually can be solved in a number of

different ways.


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2. Types of problem

Knowledge-Lean Problems: Can be solved(though not always skillfully) by use ofinstructions for the task and general problem

solving skillse.g., finding a parking space in the mall,shampooing hair

Knowledge-Rich Problems : Requires specificknowledge or skill to solve the probleme.g., calculus, computer-programmingproblems


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3. Typical Real World Problems Solving

6 Steps in Problem Solving:1. _______ the problem2. __________ the problem3. Identify ____________ to solve the problem4. _________________ to solve the problem

from the list of alternative solutions

5. ________________ that enable you to solvethe problem by the selected method.

6. _____________ the solution


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Example:a. Identify the problem. hungryb. Understand the problem Skip breakfastc. Identify alternative ways to solve

the problem.1. prepares a sandwich2. prepares instant noodle3. buy a food4. ask friends food

d. Select the best way to solve theproblem from the list ofalternative solutions.

2. prepares instant noodle

e. List instruction that enable youto solve the problem by theselected method.

1. take a kettle2. Put the water in it until it is halfway full.3. boil the water4. open the drawer5. get a packet of instant noodle6. take a bowl7. open the packet of instant noodle8. put the noodles into a bowl9. add the flavor pack10. wait until water is boil11. put the boiled water into a bowl

12. wait for 2 minutesf. Evaluate the solution Still feel hungry?


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Typical Real World Problems Solving

Problems Example

Transaction ATM Machine, Web Application

Decision Making Forecasting

Control problems Traffic Controller

Searching problems Search Engines

Sorting problems Transport Schedule


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Transaction: ATM Machine

How to draw your money at ATM machine?

1. Insert ATM card in ATM machine2. Choose a language3. Enter pin number of your ATM card4. Choose a withdrawal process5. Enter the amount of money you want to

withdraw6. Take your ATM card. Wait for your money and

transaction slip to come out.


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Transaction: Web Application

How to browse a related web page?

1. Switch on the computer2. Wait until windows is display

3. Click the browser4. Wait until the web page is display. Then enter a domain

name/web address.5. Wait until related web page is display. Then browse the

web6. If the sources are not related, enter another domain

name.7. Repeat step 5 to step 6 until the sources are complete8. Close the web .


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Decision Making: Forecasting

1. Look at the weather situation.1.1 If weather is raining then

Watch the television in the house.1.2 If weather is not raining then

Go out play football.

1. Look at the weather situation.1.1 If weather is raining then

Watch the television in the house.1.2 ELSE

Go out play football


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Question:

There are 20 balloons that colored red andyellow. You have to drop the balloons one byone into the appropriate box; the yellowballoon belongs in the yellow box and the redballoon belongs in the red box.

Control Problem: Traffic Controller


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Answer:

1. Repeat 20 times.1.1 Take one balloon.

1.1.1 If the balloon is red

Drop the balloon in the red box1.1.2 If the balloon is yellow

Drop the balloon in the yellow box


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Searching Problems: Search Engines

How to browse a related web page?

Answer:1. Input keyword in search engine

2. Check the key word with web address2.1 If keyword is match then

Display the web address

3. Repeats step 2 until all the web address is check


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Sorting Problems:

1. Copy the contents of cell A to temp.2. Copy the contents of cell B to cell A.3. Copy the contents of temp to cell B.

5 4Cell A temp Cell B
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4. What is Algorithm?

Definition:

A step by step problem solving procedure.A sequence of instructions that tell how to solve aparticular problem.A set of precise instructions for perform a computationor for solving a problem.A computable set of steps to achieve a desired result.A step by step sequence of precise instructions that mustterminates and describes how the data is processes toproduce the desired output.

No generally accepted definition.From natural languages to programming languagesCan be expressed in any language
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Input and Output:Algorithm receives input and produces theoutput.Unambiguous:Step in algorithm must be clear as to what it issupposed to do and how many times it is

expected to be executed.Correct and Efficient:An algorithm should produce the correct and

efficient output values for each set of input values.Finite :It must execute its instruction and terminate in afinite time.


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Algorithmic solutions is a series of actions /steps (algorithm) to solve a problem.

Heuristic solution is a solution that cannot bereached through a direct of steps and requirereasonable built on knowledge andexperience. (AI)


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History of AlgorithmThe word algorithmis derived from the nameof the Persian mathematician Al-Khwarizmi (Abu Abdullah Muhammad Ibn Musa Al-Khwarizmi or Abu Jafar Muhammad. (A.D. 780 850))Known as Father of Aljebra because of his

extensive work in algebra.He is great muslim mathematician, astronomerand geographer.One of the his books is base 10 positionalnumbering systems that developed in IndiaThe books described formalized, step by stepprocedures for doing arithmetic operation likeaddition, subtraction and multiplication and

introduced decimal system.
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Linear Search

SimpleCompare with key valueUseful for small and unsorted arrays.

Binary SearchFor sorted array.Compare middle elements with key.Like find a page number from a book.If key = match found. If key < middle looks in first half of array. If key > middle looks in last half of array.

Linear Search & Binary Search


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Searching examines 10, 4, 5 and 11.

Linear Search

10 4 5 11 2 8 25E.g.1 Searching for the value 2

Searching examines 10, 4, 5, 11, 2, 8, and 25.

10 4 5 11 2 8 25

E.g.2 Searching for the value 35


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Searching examines 8 and stops.

Binary Search


Searching examines 8 and 4.


Searching examines 8, 11 and 25.



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The End

Documents

Chapter 2: Introduction to Problem Solving