lists stacks

8/16/2019 Lists Stacks

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Chapter 3:Chapter 3:Abstract DataAbstract Data

TypesTypes

Lists, Stacks

Lydia Sinapova, Simpson College

Mark Allen Weiss: Data Structures and Algorithm Analysis in Java


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An ADT

• a set of objects

• a set of operations

Same set of objects ,dierent sets of operations =>

diferent ADTs

ADTs are implemented using classes,hiding implementation details:

encapsulation


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LIST ABSTRACTION

Denitin:

A linear congurationof elements, called

nodes


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Characteristics

!nsert and delete nodes in an" order

The nodes are cnnected

#ach node has t! components!nformation $data%

&in' to the ne(t node

The nodes are accessed through the

lin's bet)een them


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"ead #redecessr $ %

Nde%

S&ccess'r $ %

tai(

*or each node the node that isin front of it is calledpredecessr)

The node that is after it iscalled s&ccessr


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Ter*in(+y

"ead $rnt, rst nde-:

The node )ithout predecessor, the node thatstarts the lists

Tai( end, (ast nde-: The node that has no successor, the last

node in the list

C&rrent nde: The node being processed) *rom the current node )e can access the ne(t node

.*pty (ist: +o nodes e(ist


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Basic peratins

To createdestro" a list

To e(pandshrin' the list

-ead.rite operations

/hanging the current node $mo0ingalong the list%

To report current position in the list

To report status of the list


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ADT List Ntatin

L ' list

e ' item of the same t"pe asthe

information part of an

element$a node% in the list

b ' boolean 0alue


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Operatins in ADT

NtatinInsertL,e-!nserts a node )ith information e beforethe current position

De(eteL-

Deletes the current node in & , the

current position indicates the ne(t node

Retrie/eIn$L- e

-eturns the information in the current


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Insertin and De(etin

A) Insertin

To insert a node % bet)een thenodes A and B:

/reate a lin' from % to B

/reate a lin' from A to %,


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Insertin

X

A B


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Insertin and De(etin

B) De(etin

To delete a node % bet)een A and B:

• /reate a lin' from A to B,• -emo0e node %


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De(etin

A X B


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Nde Linkin+

0) Sin+(e (inked (ists :

#ach node contains t)o lin's 1 to thepre0ious and to the ne(t node

1) D&b(e (inked (ists :

#ach node contains a lin' onl" to the ne(t

node

3) Circ&(ar (ists: The tail is lin'ed to the head


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List I*p(e*entatin

Static 2 using an arra"

Dyna*ic 2 using linearnodes


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Array I*p(e*entatin

T)o para((e( arrays are used:

•

Inde2 array 1 the numberstored in the i1th element sho)sthe inde( of the 3ne(t3 node ,

ie node that follo)s the i1thnode

•Data array 1 used to store the


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STACS

Denitin:

The (ast stred e(e*ent

is the rst t be accessedLI4O: (ast in ' rst

&t-


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Basic peratins

#&sh: store a data item

at the top of the stac'

#p: retrie0e a dataitem from the top of thestac'


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ADT Denitin $ STAC

Ntatin:

S stac'

e item of same t"pe as

theelements of S

b boolean 0alue


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Operatins

Init5StackS-4rocedure to initiali5e S to an

empt" stac'

Destry5StackS-4rocedure to delete all elements in

S


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Operatins

Stack5.*ptyS- b6oolean function that returns

T-7# if S is empt"

Stack54&((S- b6oolean function that returns

T-7# if S is full


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A(+rith*

0) e8 ← 4op$S%1) !hi(e stack is nt e*pty

repeat98 e9 ← pop$S%

99 push$S, e8e9%

9; e8 ←pop $S%

3 push$S e8%

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