Table Of ContentHarel Cvr.QXD 16/01/2006 09:40 PM Page 1
Algorithmics
Algorithmics
The Spirit of Computing
The Spirit of Computing
T A
h
THIRD EDITION
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l
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From a review of the first edition: p
THIRD EDITION
i
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‘This book is a veritable tour de force. Harel writes with uncommon verve, i
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clarity and imagination. r
o David Harel
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‘Through the use of tantalizing questions and aptly chosen and often amusing examples,
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the author transmits to the reader the excitement and intellectual satisfaction of computer o
science research. Without the use of formal mathematics and without any sacrifice of m h with
intellectual integrity, he conveys to the general reader the profound principles on which p
computer science is founded and which hitherto were only accessible in abstruse and u m Yishai Feldman
t
esoteric textbooks and papers. i
n
‘This is scientific writing at its best.’ g i
c
Dr Stan Scott, Queen's University Belfast The Times Higher Education Supplement.
s
This book tells the story of the concepts, ideas, methods and results fundamental to computer
science, in a form independent of the details of specific computers, languages and formalisms. It
T
concerns the true ‘spirit’ of computers; with the ‘recipes’ that make them tick – their algorithms.
H
I
R
New to this edition D
■ Chapters on software engineering and on reactive systems. ED
■ Thoroughly revised chapter on programming languages. IT
■ New material on quantum and molecular computing. IO
■ Whole text thoroughly updated to include new material on many topics, including abstract N
data types, the object–oriented paradigm, primality testing, and system verification and
validation. YwD
ii
shtha
v
David Harel is Professor and Dean of the Faculty of Mathematics and Computer Science at the a
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Weizmann Institute of Science. He is renowned for outstanding research in many areas of the d
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field, and has recently been awarded the Israel Prize in Computer Science. Yishai Feldman is on e
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the faculty of the Efi Arazi School of Computer Science at the Interdisciplinary Centre, Herzliya. d
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He specializes in the use of artificial–intelligence techniques in software engineering and their a r
real–world applications. n e
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www.pearson-books.com
an imprint of
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Algorithmics
The Spirit of Computing
i
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Weworkwithleadingauthorstodevelopthe
strongesteducationalmaterialsincomputing,
bringingcutting-edgethinkingandbestlearning
practicetoaglobalmarket.
Underarangeofwell-knownimprints,including
Addison-Wesley,wecrafthighqualityprintand
electronicpublicationswhichhelpreaderstounderstand
andapplytheircontent,whetherstudyingoratwork.
Tofindoutmoreaboutthecompleterangeofour
publishing,pleasevisitusontheWorldWideWebat:
www.pearsoned.co.uk
ii
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Algorithmics
The Spirit of Computing
THIRD EDITION
David Harel
TheWeizmannInstitute
with
Yishai Feldman
TheInterdisciplinaryCenter,Herzliya
iii
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PearsonEducationLimited
EdinburghGate
Harlow
EssexCM202JE
England
andAssociatedCompaniesthroughouttheworld
VisitusontheWorldWideWebat:
www.pearsoned.co.uk
Firstpublished1987
Secondedition1992
Thirdeditionpublished2004
(cid:2)C Addison-WesleyPublishersLimited1987,1992
(cid:2)C PearsonEducationLimited2004
TherightsofDavidHarelandYishaiFeldmantobeidentifiedasauthorsofthiswork
havebeenassertedbytheminaccordancewiththeCopyright,DesignsandPatentsAct1988.
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrieval
system,ortransmittedinanyformorbyanymeans,electronic,mechanical,
photocopying,recordingorotherwise,withouteitherthepriorwrittenpermissionofthe
publisheroralicencepermittingrestrictedcopyingintheUnitedKingdomissuedbythe
CopyrightLicensingAgencyLtd,90TottenhamCourtRoad,LondonW1T4LP.
Theprogramsinthisbookhavebeenincludedfortheirinstructionalvalue.Theyhavebeen
testedwithcarebutarenotguaranteedforanyparticularpurpose.Thepublisherdoesnot
offeranywarrantiesorrepresentationsnordoesitacceptanyliabilitieswithrespecttothe
programs.
Alltrademarksusedhereinarethepropertyoftheirrespectiveowners.Theuseofany
trademarkinthistextdoesnotvestintheauthororpublisheranytrademarkownershiprights
insuchtrademarks,nordoestheuseofsuchtrademarksimplyanyaffiliationwithor
endorsementofthisbookbysuchowner.
ISBN0321117840
BritishLibraryCataloguing-in-PublicationData
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
LibraryofCongressCataloging-in-PublicationData
Harel,David,1950–
Algorithmics:thespiritofcomputing/DavidHarel,withYishaiFeldman.–3rded.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN0-321-11784-0
1.Computeralgorithms. I.Feldman,YishaiA.,1958– II.Title.
QA76.9.A43H37 2004
005.1–dc22 2004041063
10987654321
0807060504
Typesetby59in10/12ptTimes
PrintedandboundinGreatBritainbyBiddlesLtd.,GuildfordandKing’sLynn
iv
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Formydearmother,JoyceFisch
Andinmemoryofmydearfather,HaroldFisch
Belovedparentsandgiftedteachersboth
(D.H.)
Tothememoryofmydearparents,
HadassaandMosheFeldman
Fortheirunfailingloveandsupport
(Y.F.)
v
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Tellme,Ipraythee,
inwhatthygreatstrengthlies
JUDGES16:6
Behold,thisIhavefound...
countingonethingtoanother,tofindoutthesum
ECCLESIASTES7:27
vi
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Contents
Declarethethings
thataretocome
hereafter
ISAIAH41:23
Preface xi
Acknowledgments xvii
Part I. Preliminaries 1
(cid:2) 1. Introduction and Historical Review 3
or,What’sItAllAbout?
(cid:2) 2. Algorithms and Data 19
or,GettingItDone
(cid:2) 3. Programming Languages and Paradigms 49
or,GettingItDonebyComputer
Part II. Methods and Analysis 79
(cid:2) 4. Algorithmic Methods 81
or,GettingItDoneMethodically
(cid:2) 5. The Correctness of Algorithms 99
or,GettingItDoneRight
vii
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viii Contents
(cid:2) 6. The Efficiency of Algorithms 129
or,GettingItDoneCheaply
Part III. Limitations and Robustness 157
(cid:2) 7. Inefficiency and Intractability 159
or,YouCan’tAlwaysGetItDoneCheaply
(cid:2) 8. Noncomputability and Undecidability 191
or,SometimesYouCan’tGetItDoneAtAll!
(cid:2) 9. Algorithmic Universality and Its Robustness 219
or,TheSimplestMachinesThatGetItDone
Part IV. Relaxing the Rules 255
(cid:2) 10. Parallelism, Concurrency, and Alternative Models 257
or,GettingLotsofStuffDoneatOnce
(cid:2) 11. Probabilistic Algorithms 297
or,GettingItDonebyTossingCoins
(cid:2) 12. Cryptography and Reliable Interaction 317
or,GettingItDoneinSecret
Part V. The Bigger Picture 335
(cid:2) 13. Software Engineering 337
or,GettingItDoneWhenIt’sLarge
(cid:2) 14. Reactive Systems 357
or,GettingIttoBehaveProperlyOverTime
(cid:2) 15. Algorithmics and Intelligence 379
or,AreTheyBetteratItThanUs?
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Contents ix
Postscript 401
SelectedSolutions 403
BibliographicNotes 433
Index 495
