problem solving techniques3

8/13/2019 Problem Solving Techniques3

1/12

1 ProblemSolvingTechniques

PROBLEM SOLVING TECHNIQUESIMPORT NT QUESTIONS SOLVED

Index:

OnemarkquestionsPage1to2

TwomarkquestionsPage3to7

FivemarkquestionsPage8to16

QuestionscarryingTWOmarkseach

1. Whatistopdownanalysis?Mar06Ans:

Givenproblemislogicallysplitintonumbersubproblemswhichareinturnsplitintosmallerproblemssuchthat

eachsmallestproblemcanbeeasilysolved.

2. Mentionanyoneadvantageoftopdownapproach.July06Ans:

(Writeanyoneofthefollowing)

a. Itleadstoeasyunderstandabilityoftheproblem.b. Helpsinreuseofthecodetoperformaparticulartaskinanyotherprogram.c. Itavoidsduplicationincoding.d. Tasksperformedbyanypartoftheprogramcanbeeasilyidentified.e. Stepwiserefinementoftheproblemreducesthecomplexity.

3. Definethetermmodularity.Mar07,Jul09Ans:

Itisatechniquewhereagivenproblemisdividedintoanumberofselfcontainedindependentprogram

segments.Eachsegmentiscalledamoduleanditcanbecalledinanotherprogramoranothermodule.

4. Whatisthemaindisadvantageoflinearsearchmethod?Mar07,Mar10Ans:

Itislengthyasitinvolvesmorenumberofcomparisons.Alsorepeatedexistenceofanelementinthearray

cannotbedetected.

5. Whatisstructuredprogramming?Jul07Ans:Structuredprogrammingdealswithlogicandcode.Itinvolvestopdownanalysisapproachtoproducecode

fromasmallsetoflogicalconstructslikei.Sequenceii.Iterationiii.Selectionandiv.Modularity.

6. DefineSorting.Mar08Ans:

Itistheprocessofarrangingtheelementsofanarrayeitherinascendingorindescendingorder.

7. WhatisStepwiserefinement?Jul08Ans:

TheprocessofTesting,Debugging,addingthecode,deletingthecodeormodifyingthecodeateverystepofthe

programasperthetopdownanalysischartisknownasStepwiserefinement.


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8. Writeanyoneadvantageoflinearsearch.Jul08Ans:

Usingthistechniqueevenanunsortedarraycanbesearched.

9.What

is

the

other

name

of

Bubble

Sort.

Mar

09.

Ans:

ExchangeSort

10.Whatissearching?Jul09Ans:

TheprocessoffindingthepresenceandthelocationofanelementinanarrayisknownasSearching.

11.Whatisamodule?Mar10Ans:

Itisalogicallyseparatedsmallestpartofthegivenproblemwhichiscapableofperformingasingletask.

12.Whatisworstcaseinsorting?Ans:

Asortingtechniqueinvolvesnumberofexchangesofelementsbetweendifferentlocationsofthearray.A

situationwhereinamaximumnumberofexchangesareinvolvedissaidtobetheworstcaseinsorting.

QuestionscarryingTWOmarkseach

13.Whatisbinarysearch?Whenisitapplicable?Mar06Ans:

ThissearchingtechniqueissuperiortoLinearsearchbutcanbeusedonlywhenthearrayisreadily

sorted.Inthistechnique,thegivenarraytobesearchedissplitintotwoequalpartsandthesearchiscontinued

inthatpartofthearraytowhichthesearchelementbelongs.Theaboveprocessisrepeatedtilltheelementis

foundortillthearrayiscompletelysearched.

Itisapplicableonlywhenanarrayisalreadysorted.

14.Explaintheconceptofstructuredprogramming.Mar06Ans:

Structuredprogrammingdealswithlogicandcode.Itinvolvestopdownanalysisapproachtoproducecodefrom

asmallsetoflogicalconstructslikei.Sequenceii.Iterationiii.Selectionandiv.Modularity.

15.Whatdoyoumeanbysearching?Mentionanyonetype.Jul06Ans:

TheprocessoffindingthepresenceandthelocationofanelementinanarrayisknownasSearching.

LinearSearchandBinarySearch(anyonetobementioned)

16.Giveanytwoadvantagesofstructuredprogramming.Jul06Ans:

(TherearemanyadvantagesofStructuredprogramming,mentionanytwoofthefollowing)

1. Iteration:Asetofinstructionscanbeperformedrepeatedlyuntilaparticularconditionissatisfied.Thisreducesthecode.

2. Modularity:Identificationofthetaskiseasier.3. Modularity:Testinganddebuggingatthemoduleleveliseasier.4.

Modularity:

A

module

can

be

reused

at

different

part

of

the

program

or

into

any

other

program

also.


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3

5. S17.Justi

Ans:

It

is

neasie

Diffe

1.2. S3. I

18.WhaRefe

19.WhaAns:

Itis

t

techi

4.5. S6. I

20.ConsAns:

21.BriefProblemSol

election:Di

ytheneed

ecessary

to

randfaster

rentsorting

ubbleSort

electionSor

sertionSor

istopdow

:Question

issorting?

heprocess

niquesare(

ubbleSort

electionSor

sertionSor

tructatop

lyexplain

t

INPUT

radius(r)

vingTechni

ferentseto

orsortinga

sort

an

arraatanyinsta

techiniques

t

t

ndesign?

Mentionan

farranging

Mentionan

t

t

owndesign

eanalysis

o

A

ues

instruction

ndmention

as

it

becot.

are(Mentio

ar07

yonemeth

theelement

one)

tofindthe

finsertion

s

Areaof

PRO

ea=3.142*r

scanbeper

anyoneso

es

easier

to

nanyone)

d.Jul07

sof

an

arra

areaofcircl

ortmethod.

acircle

ESS

*r

formedbas

tingtechni

search

an

e

either

in

as

e.Jul07

Mar08

Radius

donwheth

ue.Mar0

lement

and

cendingor

i

OUTPUT

eraconditio

hence

acces

descendin

Area

nissatisfie

sibility

of

th

order.Diffe

ornot.

edata

is

rentsorting


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Ans:

22.Mentionthevariousprogrammingconstructsofstructuredprogramming.Mar08,Mar10Ans:

i.Sequenceii.Iterationiii.Selectionandiv.Modularity.

23.Whatisprogrammaintenance?Explainbriefly.Jul08Ans:

Inthisprocess,apartorcompleteofthecodeofanymodulemaybechangedtoperformanaddedtaskorjustto

overcomethebugs.i.e.,modificationofcode

1. Basedonthepresent/futurenewrequirementsoftheuseror2. Basedontheerrorsfacedinthepreviousexecutionsor3. Tocopeupwiththecompetitioninthemarket.Inthisprocess,apartorcompleteofthecodeofanymodulemaybechangedtoperformanaddedtaskorjustto

overcomethebugs.

24.Writeanytwopropertiesoftopdownanalysis.Mar09.Ans:

(Thereare5importantcharacteristics.MentionanyTWO)1. CodeReusability:Thealreadyavailableasamodulecanbereusedindifferentpartofthesameprogramorin

anyotherprogram.

2. Understandability:Modularityrepresentclearlythesequenceofexecutionoftheprogramandhencereducesthe

errors

and

complexity.

3. ProgramMaintenance:Inthisprocess,apartorcompleteofthecodeofanymodulemaybechangedtoperformanaddedtaskorjusttoovercomethebugs.

4. EliminationofduplicationinCoding:Amodulecanbecalledanywhereintheprogramandasmanytimesrequiredwithrewritingthecode.Thiseliminatesduplication.

5. ClearIdentificationoftasks:Thenameofanymoduleclearlyexplainsthetaskperformedbythemodule.

25.Writeanalgorithmforlinearsearch.Mar09.


5/12

5

Ans:

Step

Step

Step

Step

Step

Step

Step

Step

Step

Step

26.MenAns:

1.2.3. F

27.ConsAns:

28.Desi

Princial(P)

ProblemSol

1: Loc=1

2:ForI=0to

3:

If

(ele=A[I4: LOC

5: Got

[

6: If(LOC>=

7: Print

8: Else

9: Print

[

10:Exit

iondiffere

hile

oWhile

or,etc.,

tructatop

nan

algorit

INPUT

Ra(R

vingTechni

n1do

]

Then

=I

oStep6

[EndIf]

Endofforlo

0)then

ele,Found

ele,Notfo

EndIf]

titerative

owndesig

hmto

find

e)

ues

op]

inlocation,

nd

rogrammin

modelcha

inimumva

SI

ime(T)

SI=

LOC

constructs

ttofindth

luein

an

ar

PLEINTER

PROCESS

P*T*R)/10

.

simpleint

ayof

nvalu

EST

0

Princi

rest.

es.

pal

OUTPUT

ate ime SI


6/12


Ans:

SMALL=A[0]

POS=0

FOR

I

=

1

TO

N

1

DO

IF(A[I]


7/12


ClearIdentificationoftasks:Eachmodulecreatedshouldperformasingletaskandthenameofthemoduleshouldconveythepurposeofthemodule.

Program

Maintenance:

Solution

should

be

organized

in

such

a

way

that

adding

new

functionalities

should

not

leadanylargechangestotheoriginalsolution.

Eliminatesduplicationincoding:Aseverytaskiscodedasamodule,whichisanindependentprogramitcanberepeatedanynumberoftimesintheprogram.Thiseliminatestheneedtorepeatthesamecodeinanumberof

placesintheprogram.

Codereusability:Modulewhichhavebeencodedandworkproperlyinoneprogramcanusedinotherprograms.31.Writeanalgorithmforinsertionsort.

Ans:

32.Supposethefollowingnumbersarestoredinanarray,applybubblesort.23,3,4,36,31Ans:

\\\\\\\continuedinthenextpage...

A 23 3 4 36 31

0 1 2 3 4


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33.ExplainthestepsinvolvedinBinarySearchmethodwithanexample.Ans:

Thisisthesimplesttechniqueofsearchinganelementinanarraythoughitismoretimeconsuming.

Inthistechnique,theelementinsearchiscomparedwitheachelementofthearrayoneatatimestartingfrom

thelowestpositionofthearraytillthesearchissuccessfulortillthewholearrayissearched.

Example:

Refer

qn.number

43.

34.WritethestepsinvolvedinperformingBinarySearchforthefollowing.32,48,56,79,82,99

Ans:

Letthearraybe

N=6

Searchelementbe,ele=79

Step1:

A 32 48 56 79 82 99

0 1 2 3 4 5


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LOW=0

HIGH=N1=61=5

MID=(LOW+HIGH)/2=(0+5)/2=2

A[MID]=56

Step2:CompareA[MID]withele.56isnotequalto79

Step3:Checkwhetherthesearchelementisgreaterthanmidorlesser.79isgreaterthan56.

Step4:Change,LOW=MID+1=2+1=3

Step5:MID=(LOW+HIGH)/2=(3+5)/2=4

A[MID]=82

Step6:Checkwhetherthesearchelementisgreaterthanmidorlesser.79issmallerthan82.

Step4:Change,HIGH=MID 1=4 1=3

Step7:MID=(LOW+HIGH)/2=(3+3)/2=3

A[MID]=79

Step8:

Check

whether

the

search

element

is

greater

than

mid

or

lesser.

They

are

same.

Hence

Search

is

completed.

Result:Thesearchelementele=79isfoundthearrayAatlocation,LOC=3

35.Sortthefollowingelementsusingselectionsort.Ans:

Considerthearray:

Pass1:

Steps:

i. 5and4arecomparedand4issmall.ii. 4iscomparedwith14and4isonlysmalliii. 4iscomparedwith10and4isfoundsmalliv. 4iscomparedwith1and1isfoundsmall

Therefore1isinterchangedwith5andtheresultingarrayis

Theabovestepsarerepeatedinthecomingpassesandtheresultantarrayinthepassesareasbelow.

Pass2:

Pass3:

A 5 4 14 10 1

0 1 2 3 4

A 1 4 14 10 5

0 1 2 3 4

A 1 4 14 10 5

0 1 2 3 4

A 1 4 5 10 14

0 1 2 3 4


10/12


Pass4:

Andhencethearrayissortedintheincreasingorder.

36.Whatisstructuredprogramming? Listadvantagesofit.Ans:

Refertoquestions5and16

37.WriteanalgorithmtosearchanelementinanarrayusingBinarysearch.Ans:

38.Explainthebinarysearchmethodwithasuitableexample.Ans:

Binarysearchalgorithmisusedtosearchforanelementinasortedlist.Thevalueoftheelementinthe

middleofthelistiscomparedwiththevalueoftheelementtobesearchedfor.Inthemiddleelementislarger,

thedesiredelementhastobeinthefirstpartofthelist,ifitispresent.Ifthemiddleelementissmaller,the

desiredelementhastobesecondhalfofthelist.Hencethesearchiscontinuedonlythedesiredpartofthearray.

Ineverysuchcomparison,thelengthofthearraytobesearchedbecomeshalf.

Example:

A 1 4 5 10 14

0

1

2

3

4

A

1

4

14

15

25


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Letussearchofelement15inthearray

Mid=(low+high)/2=(0+4)/2=2

Therefore

mid

element

is

A[mid]=

A[2]=14

Now,themidelementofthearrayis14.Andthesearchelement15isgreaterhenceitmustlieinthesecondhalf

ofthearray.Hencethearraytobesearchedisonly

Mid=(low+high)/2=(3+4)/2=3

ThereforemidelementisA[mid]=A[3]=15

Now,themidelementofthearrayis15.Andthesearchelement15issameasthemidelement.

Result:The

search

element

15

is

found

at

A[3].

39.Writeanalgorithmtofindthemaximumelementinanarray.Ans:

40.Tracebinarysearchalgorithmtofindthelocationoftheelement22inthefollowinglist.22,33,49,57,75.Ans:


Mid=(LOW+HIGH)/2

=(0+4)/2=2

ThereforemidelementisA[MID]=A[2]=49

Now,themidelementofthearrayis14.Andthesearchelement22issmallerhenceitmustlieintheFIRSThalf

ofthearray.Hencethearraytobesearchedisonly

Mid=(LOW+HIGH)/2= (0+1)/2=0

ThereforemidelementisA[MID]=A[0]=22

Now,themidelementofthearrayis22.Andthesearchelement22issameasthemidelement.

Result:Thesearchelement22isfoundatA[0].

0

Low

1 2

Mid

3 4

High

15 25

3

Low

4

High

A 22 33 49 57 75

0

Low1

2

Mid3

4

High

A 22 33

0

LOW

1

HIGH


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41.Writeanalgorithmforselectionsorttechnique.Ans:

42.Applylinearsearchmethodtofindthevalue43inanarraycontainingthefollowingvalues.38,40,31,28,43,45,60.

Ans:


Letthesearchelementbeele=43

Step1:CompareelewithA[0],theyarenotsame.




Step5:CompareelewithA[4],theyaresame.

Stopthe

search

and

declare

the

result

as,

the

search

element

is

found

at

A[4].

Youcanalsodownloadthesoftcopyofthismaterialbyusingtheurlgivenbelow.

www.npscience.com

or

forum.npscience.com

by

NawabPasha

A 38 40 31 28 43 45 60

0 1 2 3 4 5 6

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