Python Unit 1.pdfPython Notes for Bharathiar university syllabus

GE8151 PROBLEM SOLVING AND PYTHON PROGRAMMING
UNIT I
ALGORITHMIC PROBLEM SOLVING
Algorithms, building blocks of algorithms (statements, state, control flow, functions),
notation (pseudo code, flow chart, programming language), algorithmic problem
solving, simple strategies for developing algorithms (iteration, recursion). Illustrative
problems: find minimum in a list, insert a card in a list of sorted cards, Guess an
integer number in a range, Towers of Hanoi.
1.PROBLEM SOLVING
Problem solving is the systematic approach to define the problem and creating
number of solutions.
The problem solving process starts with the problem specifications and ends with a
Correct program.
1.1 PROBLEM SOLVING TECHNIQUES
Problem solving technique is a set of techniques that helps in providing logic for solving
a problem.
Problem Solving Techniques/Program Design Tools:
Problem solving can be expressed in the form of
1. Algorithms.
2. Flowcharts.
3. Pseudo codes.
1.2.ALGORITHM
Algorithm is an ordered sequence of finite, well defined, unambiguous
instructions for completing a task. It is an English-like representation of the logic which
is used to solve the problem. It is a step- by-step procedure for solving a task or a
problem.
It is also defined as “any problem whose solution can be expressed in a list of
executable instruction”.
It is defined as a sequence of instructions that describe a method for solving a
problem. In other words it is a step by step procedure for solving a problem.
Example- Algorithm to display your name ,dept
1. Start
2. Get/Read the name and department
3. Print the name and department
4. Stop
Algorithm to find the area of the circle
1. Start
2. Read the value of radius r
3. Calculate - Area=3.14*r*r
4. Print the Area of the circle
5. Stop
Programs

Characteristics of algorithm
 Should be written in simple English
 Each and every instruction should be precise and unambiguous.

 Instructions in an algorithm should not be repeated infinitely.
 Algorithm should conclude after a finite number of steps.
 Should have an end point
 Derived results should be obtained only after the algorithm terminates.

Qualities of a good algorithm
The following are the primary factors that are often used to judge the quality of the
algorithms.

Time – To execute a program, the computer system takes some amount of time. The
lesser is the time required, the better is the algorithm.

Memory – To execute a program, computer system takes some amount of memory
space. The lesser is the memory required, the better is the algorithm.

Accuracy – Multiple algorithms may provide suitable or correct solutions to a given
problem, some of these may provide more accurate results than others, and such
algorithms may be suitable.
Or
Qualities of a good algorithm
Time - Lesser time required.
Memory - Less memory required.
Accuracy - Suitable or correct solution obtained.
Sequence - Must be sequence and some instruction may be repeated in number of
times or until particular condition is met.
Generability - Used to solve single problem and more often algorithms are designed to
handle a range of input data.
2.BUILDING BLOCKS OF ALGORITHMS (statements, state, control flow, functions)
Algorithms can be constructed from basic building blocks namely, sequence,
selection and iteration.
2.1.Statements:
Statement is a single action in a computer.
In a computer statements might include some of the following actions
 input data-information given to the program
 process data-perform operation on a given input
 output data-processed result
2.2.State:
Transition from one process to another process under specified condition with in a
time is called state.

2.3.Control flow:
The process of executing the individual statements in a given order is called control
flow.
The control can be executed in three ways
1. sequence
2. selection
3. iteration
Sequence:
All the instructions are executed one after another is called sequence execution.
Example:
Add two numbers:
Step 1: Start
Step 2: get a,b
Step 3: calculate c=a+b
Step 4: Display c
Step 5: Stop
Selection:
A selection statement causes the program control to be transferred to a specific
part of the program based upon the condition.
If the conditional test is true, one part of the program will be executed, otherwise
it will execute the other part of the program.
Example
Write an algorithm to check whether he is eligible to vote?
Step 1: Start
Step 2: Get age
Step 3: if age >= 18 print “Eligible to vote”
Step 4: else print “Not eligible to vote”
Step 6: Stop

Iteration:
In some programs, certain set of statements are executed again and again based
upon conditional test. i.e. executed more than one time. This type of execution is called
looping or repetition or iteration.
Example
Write an algorithm to print all natural numbers up to n
Step 1: Start
Step 2: get n value.
Step 3: initialize i=1
Step 4: if (i<=n) go to step 5 else go to step 7
Step 5: Print i value and increment i value by 1
Step 6: go to step 4
Step 7: Stop
2.4.Functions:
 Function is a sub program which consists of block of code(set of instructions)
that performs a particular task.

 For complex problems, the problem is been divided into smaller and simpler
tasks during algorithm design.
Benefits of Using Functions
 Reduction in line of code

 code reuse

 Better readability

 Information hiding

 Easy to debug and test

 Improved maintainability
Example:
Algorithm for addition of two numbers using function
Main function()
Step 1: Start
Step 2: Call the function add()
Step 3: Stop
sub function add()
Step 1: Function start
Step 2: Get a, b Values
Step 3: add c=a+b
Step 4: Print c
Step 5: Return

3.NOTATIONS
3.1.FLOW CHART
Flow chart is defined as graphical or diagrammatic representation of the logic for
problem solving.
The purpose of flowchart is making the logic of the program clear in a visual
representation.
A flowchart is a picture of the separate steps of a process in sequential order.

Rules for drawing a flowchart
1. The flowchart should be clear, neat and easy to follow.
2. The flowchart must have a logical start and finish.
3. Only one flow line should come out from a process symbol.
4. Only one flow line should enter a decision symbol. However, two or three flow
lines may leave the decision symbol.
5. Only one flow line is used with a terminal symbol.
6. Within standard symbols, write briefly and precisely.
7. Intersection of flow lines should be avoided.
Advantages/Benefits of flowchart:
1. Communication: - Flowcharts are better way of communicating the logic of a
system to all concerned.
2. Effective analysis: - With the help of flowchart, problem can be analyzed in more
effective way.

3. Proper documentation: - Program flowcharts serve as a good
program documentation, which is needed for various purposes.
4. Efficient Coding: - The flowcharts act as a guide or blueprint during
the systems analysis and program development phase.
5. Proper Debugging: - The flowchart helps in debugging process.
6. Efficient Program Maintenance: - The maintenance of operating
program
becomes easy with the help of flowchart. It helps the programmer to
put efforts more efficiently on that part.
Disadvantages/Limitation of using flowchart
1. Complex logic: - Sometimes, the program logic is quite complicated.
In that case, flowchart becomes complex and clumsy.
2. Alterations and Modifications: - If alterations are required the
flowchart may require re-drawing completely.
3. Reproduction: - As the flowchart symbols cannot be typed,
reproduction of flowchart becomes a problem.
4. Cost: For large application the time and cost of flowchart drawing
becomes costly.
GUIDELINES FOR DRAWING A FLOWCHART
Flowcharts are usually drawn using some standard symbols; however, some special symbols
can also be developed when required. Some standard symbols, which are frequently required for
flowcharting many computer programs.
Terminator:

An oval flow chart shape indicates the start or end of the process, usually containing the
word “Start” or “End”.
Terminator
Process:
A rectangular flow chart shape indicates a normal/generic process flow step. For
example, “Add 1 to X”, “M = M*F” or similar.
Process
Decision:
A diamond flow chart shape indicates a branch in the process flow. This symbol is
used when a decision needs to be made, commonly a Yes/No question or True/False test.
Decision
No
Yes

Connector:

A small, labelled, circular flow chart shape used to indicate a jump in the process flow.
Connectors are generally used in complex or multi-sheet diagrams.
Data:
A parallelogram that indicates data input or output (I/O) for a process. Examples: Get X
from the user, Display X.
Delay:

Used to indicate a delay or wait in the process for input from some other process.





Arrow:
Used to show the flow of control in a process. An arrow coming from one symbol and
ending at another symbol represents that control passes to the symbol the arrow points to.

Example Flowchart
Problem 1: Draw the flowchart to find the largest number between A and B
Problem 2: Find the area of a circle of radius r.

Problem 3: Convert temperature Fahrenheit to Celsius.
Problem 4: Flowchart for an algorithm which gets two numbers and prints sum of their value
.

Problem5: Flowchart for the problem of printing even numbers between 0 and 99.

3.2.PSEUDO CODE:
“Pseudo” means initiation or false.
“Code” means the set of statements or instructions written in a programming
language. Pseudocode is also called as “Program Design Language [PDL]”.

 Pseudo code consists of short, readable and formally styled English languages
used for explaining an algorithm.

 It does not include details like variable declaration, subroutines.

 It is easier to understand for the programmer or non programmer to understand
the general working of the program, because it is not based on any programming
language.

 It gives us the sketch of the program before actual coding.
 It is not a machine readable
 Pseudo code can’t be compiled and executed.
 There is no standard syntax for pseudo code.

Rules for writing Pseudocode
 Write one statement per line
 Capitalize initial keyword(READ, WRITE, IF, WHILE, UNTIL).

 Indent to hierarchy
 End multiline structure
 Keep statements language independent

Common keywords used in pseudocode
The following gives common keywords used in pseudocodes. 1.
//: This keyword used to represent a comment.
2. BEGIN,END: Begin is the first statement and end is the last statement.
3. INPUT, GET, READ: The keyword is used to inputting data.
4. COMPUTE, CALCULATE: used for calculation of the result of the given expression.
5. ADD, SUBTRACT, INITIALIZE used for addition, subtraction and initialization.

6. OUTPUT, PRINT, DISPLAY: It is used to display the output of the program.
7. IF, ELSE, ENDIF: used to make decision.
8. WHILE, ENDWHILE: used for iterative statements.
9. FOR, ENDFOR: Another iterative incremented/decremented tested automatically.
Example:
Addition of two numbers:
BEGIN
GET a,b
ADD c=a+b
PRINT c
END

Syntax for if else: Example: Greates of two numbers
IF (condition)THEN BEGIN
statement READ a,b
... IF (a>b) THEN
ELSE DISPLAY a is greater
statement ELSE
... DISPLAY b is greater
ENDIF END IF
END
Syntax for For: Example: Print n natural numbers
FOR( start-value to end-value) DO BEGIN
statement GET n
... INITIALIZE i=1
ENDFOR FOR (i<=n) DO
PRINT i
i=i+1
ENDFOR
END
Syntax for While: Example: Print n natural numbers
WHILE (condition) DO BEGIN
statement GET n
... INITIALIZE i=1
ENDWHILE WHILE(i<=n) DO
PRINT i
i=i+1
ENDWHILE
END
Advantages:
 Pseudo is independent of any language; it can be used by most programmers.
 It is easy to translate pseudo code into a programming language.
 It can be easily modified as compared to flowchart.

 Converting a pseudo code to programming language is very easy as compared
with converting a flowchart to programming language.
 It does not provide visual representation of the program’s logic.
 There are no accepted standards for writing pseudo codes.
 It cannot be compiled nor executed.
 For a beginner, It is more difficult to follow the logic or write pseudo code as
compared to flowchart.
Disadvantage
It is not visual.
We do not get a picture of the design.
There is no standardized style or format.
For a beginner, it is more difficult to follow the logic or write pseudocode as
compared to flowchart.

Algorithm Flowchart Pseudo code
An algorithm is a sequence It is a graphical It is a language
of instructions used to representation of algorithm representation of
solve a problem algorithm.
User needs knowledge to not need knowledge of Not need knowledge of
write algorithm. program to draw or program language to
understand flowchart understand or write a
pseudo code.

4.ALGORITHMIC PROBLEM SOLVING:
Algorithmic problem solving is solving problem that require the formulation of an
algorithm for the solution.
Understanding the Problem
 It is the process of finding the input of the problem that the algorithm solves.
 It is very important to specify exactly the set of inputs the algorithm needs to
handle.

 A correct algorithm is not one that works most of the time, but one that works
correctly for all legitimate inputs.
Ascertaining the Capabilities of the Computational Device
If the instructions are executed one after another, it is called sequential
algorithm.
 If the instructions are executed concurrently, it is called parallel algorithm.

Choosing between Exact and Approximate Problem Solving
 The next principal decision is to choose between solving the problem exactly or
solving it approximately.

 Based on this, the algorithms are classified as exact algorithm and approximation
algorithm.
 Data structure plays a vital role in designing and analysis the algorithms.
 Some of the algorithm design techniques also depend on the structuring data
specifying a problem’s instance

 Algorithm+ Data structure=programs.
Algorithm Design Techniques
 An algorithm design technique (or “strategy” or “paradigm”) is a general
approach to solving problems algorithmically that is applicable to a variety of
problems from different areas of computing.

 Learning these techniques is of utmost importance for the following reasons.
 First, they provide guidance for designing algorithms for new problems,
 Second, algorithms are the cornerstone of computer science
Methods of Specifying an Algorithm
 Pseudocode is a mixture of a natural language and programming language-like
constructs. Pseudocode is usually more precise than natural language, and its
usage often yields more succinct algorithm descriptions.

 In the earlier days of computing, the dominant vehicle for specifying algorithms
was a flowchart, a method of expressing an algorithm by a collection of
connected geometric shapes containing descriptions of the algorithm’s steps.

 Programming language can be fed into an electronic computer directly. Instead,
it needs to be converted into a computer program written in a particular
computer language. We can look at such a program as yet another way of
specifying the algorithm, although it is preferable to consider it as the algorithm’s
implementation.
 Once an algorithm has been specified, you have to prove its correctness. That is,
you have to prove that the algorithm yields a required result for every legitimate
input in a finite amount of time.

 A common technique for proving correctness is to use mathematical induction
because an algorithm’s iterations provide a natural sequence of steps needed for
such proofs.

 It might be worth mentioning that although tracing the algorithm’s performance
for a few specific inputs can be a very worthwhile activity, it cannot prove the
algorithm’s correctness conclusively. But in order to show that an algorithm is
incorrect, you need just one instance of its input for which the algorithm fails.

Analysing an Algorithm
1. Efficiency.
Time efficiency, indicating how fast the algorithm runs,
Space efficiency, indicating how much extra memory it uses.
2. simplicity.
 An algorithm should be precisely defined and investigated with mathematical
expressions.

 Simpler algorithms are easier to understand and easier to program.
 Simple algorithms usually contain fewer bugs.
Coding an Algorithm
 Most algorithms are destined to be ultimately implemented as computer
programs. Programming an algorithm presents both a peril and an opportunity.

 A working program provides an additional opportunity in allowing an empirical
analysis of the underlying algorithm. Such an analysis is based on timing the
program on several inputs and then analysing the results obtained.
5.SIMPLE STRATEGIES FOR DEVELOPING ALGORITHMS:
1. iterations
2. Recursions
5.1.Iterations:
A sequence of statements is executed until a specified condition is true is called
iterations.
1. for loop
2. While loop
Syntax for For: Example: Print n natural numbers
BEGIN
FOR( start-value to end-value) DO GET n
statement INITIALIZE i=1
... FOR (i<=n) DO
ENDFOR PRINT i
i=i+1
ENDFOR
END
Syntax for While: Example: Print n natural numbers
BEGIN
WHILE (condition) DO GET n
statement INITIALIZE i=1
... WHILE(i<=n) DO
ENDWHILE PRINT i
i=i+1
ENDWHILE
END

5.2.Recursions:
 A function that calls itself is known as recursion.
 Recursion is a process by which a function calls itself repeatedly until some
specified condition has been satisfied.
Algorithm for factorial of n numbers using recursion:
Main function:
Step1: Start
Step2: Get n
Step3: call factorial(n)
Step4: print fact
Step5: Stop
Sub function factorial(n):
Step1: if(n==1) then fact=1 return fact
Step2: else fact=n*factorial(n-1) and return fact

Pseudo code for factorial using recursion:
Main function:
BEGIN
GET n
CALL factorial(n)
PRINT fact
BIN
Sub function factorial(n):
IF(n==1) THEN
fact=1
RETURN fact
ELSE
RETURN fact=n*factorial(n-1)

More examples:
Write an algorithm to find area of a rectangle
Step 1: Start BEGIN
Step 2: get l,b values READ l,b
Step 3: Calculate A=l*b CALCULATE A=l*b
Step 4: Display A DISPLAY A
Step 5: Stop END
Write an algorithm for Calculating area and circumference of circle
Step 1: Start BEGIN
Step 2: get r value READ r
Step 3: Calculate A=3.14*r*r CALCULATE A and C
Step 4: Calculate C=2.3.14*r A=3.14*r*r
Step 5: Display A,C C=2*3.14*r
Step 6: Stop DISPLAY A
END

Write an algorithm for Calculating simple interest
Step 1: Start
Step 2: get P, n, r value BEGIN
Step3:Calculate READ P, n, r
SI=(p*n*r)/100 CALCULATE S
Step 4: Display S SI=(p*n*r)/100
Step 5: Stop DISPLAY SI
END
Write an algorithm for Calculating engineering cutoff
Step 1: Start
Step2: get P,C,M value BEGIN
Step3:calculate READ P,C,M
Cutoff= (P/4+C/4+M/2) CALCULATE
Step 4: Display Cutoff Cutoff= (P/4+C/4+M/2)
Step 5: Stop DISPLAY Cutoff
END
To check greatest of two numbers
Step 1: Start
Step 2: get a,b value
Step 3: check if(a>b) print a is greater
Step 4: else b is greater
Step 5: Stop

BEGIN
READ a,b
IF (a>b) THEN
DISPLAY a is greater
ELSE
DISPLAY b is greater
END IF
END
To check leap year or not
Step 1: Start
Step 2: get y
Step 3: if(y%4==0) print leap year
Step 4: else print not leap year
Step 5: Stop
BEGIN
READ y
IF (y%4==0) THEN
DISPLAY leap year
ELSE
DISPLAY not leap year
END IF
END

To check positive or negative number
Step 1: Start
Step 2: get num
Step 3: check if(num>0) print a is positive
Step 4: else num is negative
Step 5: Stop
BEGIN
READ num
IF (num>0) THEN
DISPLAY num is positive
ELSE
DISPLAY num is negative
END IF
END

To check odd or even number
Step 1: Start
Step 2: get num
Step 3: check if(num%2==0) print num is even
Step 4: else num is odd
Step 5: Stop
BEGIN
READ num
IF (num%2==0) THEN
DISPLAY num is even
ELSE
DISPLAY num is odd
END IF
END
To check greatest of three numbers
Step1: Start
Step2: Get A, B, C
Step3: if(A>B) goto Step4 else goto step5
Step4: If(A>C) print A else print C
Step5: If(B>C) print B else print C
Step6: Stop

BEGIN
READ a, b, c
IF (a>b) THEN
IF(a>c) THEN
DISPLAY a is greater
ELSE
DISPLAY c is greater
END IF
ELSE
IF(b>c) THEN
DISPLAY b is greater
ELSE
DISPLAY c is greater
END IF
END IF
END
Write an algorithm to check whether given number is +ve, -ve or zero.
Step 1: Start
Step 2: Get n value.
Step 3: if (n ==0) print “Given number is Zero” Else goto step4
Step 4: if (n > 0) then Print “Given number is +ve”
Step 5: else Print “Given number is -ve”
Step 6: Stop

BEGIN
GET n
IF(n==0) THEN
DISPLAY “ n is zero”
ELSE
IF(n>0) THEN
DISPLAY “n is positive”
ELSE
DISPLAY “n is positive”
END IF
END IF
END

Write an algorithm to print all natural numbers up to n
Step 1: Start
Step 2: get n value.
Step 3: initialize i=1
Step 4: if (i<=n) go to step 5 else go to step 8
Step 5: Print i value
step 6 : increment i value by 1
Step 7: go to step 4
Step 8: Stop
BEGIN
GET n
INITIALIZE i=1
WHILE(i<=n) DO
PRINT i
i=i+1
ENDWHILE
END

Write an algorithm to print n odd numbers
Step 1: start
step 2: get n value
step 3: set initial value i=1
step 4: check if(i<=n) goto step 5 else goto step 8
step 5: print i value
step 6: increment i value by 2
step 7: goto step 4
step 8: stop
BEGIN
GET n
INITIALIZE i=1
WHILE(i<=n) DO
PRINT i
i=i+2
ENDWHILE
END

Write an algorithm to print n even numbers
Step 1: start
step 2: get n value
step 4: check if(i<=n) goto step 5 else goto step8
step 5: print i value
step 7: goto step 4
step 8: stop
BEGIN
GET n
INITIALIZE i=2
WHILE(i<=n) DO
PRINT i
i=i+2
ENDWHILE
END

Write an algorithm to print squares of a number
Step 1: start
step 2: get n value
step 4: check i value if(i<=n) goto step 5 else goto step8
step 5: print i*i value
step 7: goto step 4
step 8: stop
BEGIN
GET n
INITIALIZE i=1
WHILE(i<=n) DO
PRINT i*i
i=i+2
ENDWHILE
END

Write an algorithm to print to print cubes of a number
Step 1: start
step 2: get n value
step 4: check i value if(i<=n) goto step 5 else goto step8
step 5: print i*i *i value
step 7: goto step 4
step 8: stop
BEGIN
GET n
INITIALIZE i=1
WHILE(i<=n) DO
PRINT i*i*i
i=i+2
ENDWHILE
END

Write an algorithm to find sum of a given number
Step 1: start
step 2: get n value
step 3: set initial value i=1, sum=0
Step 4: check i value if(i<=n) goto step 5 else goto step8
step 5: calculate sum=sum+i
step 7: goto step 4
step 8: print sum value
step 9: stop
BEGIN
GET n
INITIALIZE i=1,sum=0
WHILE(i<=n) DO
sum=sum+i
i=i+1
ENDWHILE
PRINT sum
END
29

Write an algorithm to find factorial of a given number
Step 1: start
step 2: get n value
step 3: set initial value i=1, fact=1
Step 4: check i value if(i<=n) goto step 5 else goto step8
step 5: calculate fact=fact*i
step 7: goto step 4
step 8: print fact value
step 9: stop
BEGIN
GET n
INITIALIZE i=1,fact=1
WHILE(i<=n) DO
fact=fact*i
i=i+1
ENDWHILE
PRINT fact
END

ILLUSTRATIVE PROBLEM
1.Guess an integer in a range
Algorithm:
Step1: Start
Step 2: Declare hidden, guess,range=1 to 100
Step 3: Compute hidden= Choose a random value in a range
Step 4: Read guess
Step 5: If guess=hidden, then Print
Guess is hit
Else
Print Guess not hit
Print hidden
Step 6: Stop
Pseudocode:
BEGIN
COMPUTE hidden=random value in a range
READ guess
IF guess=hidden, then PRINT
Guess is hit
ELSE
PRINT Guess not hit
PRINT hidden
END IF-ELSE
END
Flowchart:

2.Find minimum in a list
Algorithm: Step 1:
Start Step 2: Read n
Step 3:Initialize i=0
Step 4: If i<n, then goto step 4.1, 4.2 else goto step 5
Step4.1: Read a[i]
Step 4.2: i=i+1 goto step 4
Step 5: Compute min=a[0]
Step 6: Initialize i=1
Step 7: If i<n, then go to step 8 else goto step 10
Step 8: If a[i]<min, then goto step 8.1,8.2 else goto 8.2
Step 8.1: min=a[i]
Step 8.2: i=i+1 goto 7
Step 9: Print min
Step 10: Stop
Pseudocode:
BEGIN
READ n
FOR i=0 to n, then READ
a[i] INCREMENT
i
END FOR COMPUTE
min=a[0] FOR i=1 to n,
then
IF a[i]<min, then CALCULATE
min=a[i] INCREMENT i
ELSE
INCREMENT i
END IF-ELSE
END FOR
PRINT min
END

3.Insert a card in a list of sorted cards
Algorithm: Step 1:
Start Step 2: Read n
Step 3:Initialize i=0
Step4.1: Read a[i]
Step 4.2: i=i+1 goto step 4
Step 5: Read item
Step 6: Calculate i=n-1
Step 7: If i>=0 and item<a[i], then go to step 7.1, 7.2 else goto step 8
Step 7.1: a[i+1]=a[i]
Step 7.2: i=i-1 goto step 7
Step 8: Compute a[i+1]=item
Step 9: Compute n=n+1
Step10.1: Print a[i]
Step10.2: i=i+1 goto step 10
Step 11: Stop
Pseudocode:
BEGIN
READ n
FOR i=0 to n, then READ
a[i] INCREMENT
i
END FOR
READ item
FOR i=n-1 to 0 and item<a[i], then
CALCULATE a[i+1]=a[i]
DECREMENT i
END FOR COMPUTE
a[i+1]=a[i] COMPUTE
n=n+1 FOR i=0 to n, then
PRINT a[i]
INCREMENT i
END FOR
END

4. Tower of Hanoi
Algorithm:
Step 1: Start
Step 2: Read n
Step 3: Calculate move=pow(2,n)-1
Step 4: Function call T(n,Beg,Aux,End) recursively until n=0
Step 4.1: If n=0, then goto step 5 else goto step 4.2 Step
4.2: T(n-1,Beg,End,Aux)
T(1,Beg,Aux,End) , Move disk from source to destination
T(n-1,Aux,Beg,End)
Step 5: Stop
Pseudcode:
BEGIN
READ n
CALCULATE move=pow(2,n)-1
FUNCTION T(n,Beg,Aux,End) Recursively until n=0
PROCEDURE IF
n=0 then,
No disk to move
Else
T(n-1,Beg,End,Aux)
T(1,Beg,Aux,End), move disk from source to destination
T(n-1,Aux,Beg,End)
END PROCEDURE
END
Flowchart:

Procedure to solve Tower of Hanoi
The goal of the puzzle is to move all the disks from leftmost peg to rightmost peg.
1. Move only one disk at a time.
2. A larger disk may not be p1aced on top of a smaller disk.
For example, consider n=3 disks

Python Unit 1.pdfPython Notes for Bharathiar university syllabus

Python Unit 1.pdfPython Notes for Bharathiar university syllabus

Recommended

More Related Content

What's hot (20)

Similar to Python Unit 1.pdfPython Notes for Bharathiar university syllabus (20)

More from ANUSUYA S (15)

Recently uploaded (20)

Python Unit 1.pdfPython Notes for Bharathiar university syllabus