2.linked list

8/8/2019 2.Linked List

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LINKED LISTS

A linked list is a non sequential collection

of data items called nodes


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LINKED LISTS

Each node in a linked list has basically two

fields Data field

Link field


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LINKED LISTS

The data field contains an actual value to

be stored and processed

The link field contains the address of the

next data item in the linked list

Data field Link field


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LINKED LISTS

The logical and physical ordering of dataitems in a linked list need not be the same

The link field of the last node contains

NULL rather than a valid address

It is a null pointer and indicates the end of

the list


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LINKED LISTS

EMPTY LIST

If the nodes are not present in a linked list,

then it is called an empty linked list or

empty list

It is also called the null list


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LINKED LISTS

REPRESENTATION OF LINEAR LINKED LIST

The linear linked list can be represented in memorywith the following declarations

class node

{ int data;

node link;

node(int val){ data=val;link=null;

}}


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LINKED LISTS

A new node can be created using

node freshnode= new node(value);

It can be accessed as

freshnode.data

freshnode.link


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LINKED LISTS

OPERATION ON LINKED LIST

The basic operations to be performed on the

linked lists are Creation

Insertion

Deletion Traversing

Searching

Display


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LINKED LISTS

Creation

This operation is used to create a linked list


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LINKED LISTS

Insertion

This operation is used to insert a new node in

the linked list at the specified position. Anew node may be inserted

At the beginning of a linked list

At the end of a linked list At the specified position in linked list

If the list itself is empty, then the new node

is inserted as a first node


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LINKED LISTS

Deletion

This operation is used to delete a node from

the linked list. A node may be deleted from

the

Beginning of a linked list End of a linked list

Specified item in the list


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LINKED LISTS

Traversing

It is a process of going through all the

nodes of a linked list from one end to the

other end


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LINKED LISTS

Searching

This operation is used to search a particularelement in a linked list

If the desired element is found, we signaloperation SUCCESSFUL, otherwiseUNSUCCESSFULL


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LINKED LISTS

Display

This operation is used to print each and

every nodes information


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LINKED LISTS

TYPES OF LINKED LIST

We can put linked list into the followingtypes

Singly linked list

Doubly linked list

Circular linked list

Circular doubly linked list


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LINKED LISTS

Singly Linked List (Linear Linkedlist) A Singly linked list is one in which all

nodes are linked together in some

sequential manner

10 20 30 40 nullstart


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LINKED LIST

Doubly Linkedlist

A doubly linked list is one in which all

nodes are linked together by multiple links

which help in accessing both the successornode (next node) and predecessor node

(previous node) for any arbitrary node

within the list


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LINKED LIST

Doubly Linkedlist

Each node in a doubly linked list has two

pointer fields Pointer to left node

Pointer to right node

20 5 15 nullnull

10

start

left data right


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LINKED LISTS

Circular Linked List

A Circular linked list is one which has nobeginning and no end

10 20 30 40start


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LINKED LIST

Circular Doubly Linkedlist

A circular doubly linked list is one which

has both the successor pointer andpredecessor pointer in circular manner

20 5 1510

start

left data right


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LINKED LIST

ADVANTAGES

Linked lists are dynamic data structures

can grow and shrink during the execution of aprogram

Efficient memory utilization

Memory is not pre-allocated

Insertion and deletions are easier and

efficient


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LINKED LIST

DISADVANTAGES

More memory If the number of fields are more, then more

memory space is needed

Access to an arbitrary data item is little bit

cumbersome and also time consuming


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LINKED LIST

Insertinganodeatthebeginning


32 null

newnode


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LINKED LIST

Insertinganodeatthebeginning


32

newnode


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LINKED LIST

Void insert_at_begin(int item){

node newnode=new node(item);if (start!=null)

newnode.link=start;

start=newnode;

}


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LINKED LIST

Insertinganodeattheend


32 null

newnode


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LINKED LIST



32 null

newnode

loc


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LINKED LIST


20 40 25 48start

32 null

newnode

loc


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LINKED LIST


Void insert_at_end(int item){ node newnode=new node(item);

loc=start;

while (loc.link!=null)loc=loc.link;

loc.link=newnode;

}


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LINKED LIST

Insertinganewnodeatthespecified

position


32 null

newnode

Insert a new node after

the second node


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LINKED LIST


position


32 null

newnode

loc


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LINKED LIST


position


32

newnode

loc


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LINKED LIST

Insertinganewnodeatthespecifiedposition

Void insert_specific_position(int item, int pos){ node newnode= new node(item);

loc=start; temp=1;

while(temp


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LINKED LIST

Deletingthefirstnode



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LINKED LIST

Deletingthefirstnode

Void delete_firstnode(){ if (start!= null)

start=start.link;

}


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LINKED LIST

Deletingthelastnode



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LINKED LIST

Deletingthelastnode


prev last


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LINKED LIST

Deletingthelastnode

20 40 25 null 48 nullstart

prev last


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LINKED LIST

Deletingthelastnode

Void delete_lastnode(){ last=start;

while(last.link!=null){ prev=last;

last=last.link;

}

prev.link=null;

}


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LINKED LIST

Deletingthenodecontainingaparticular

item

Delete the node containing value 25



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LINKED LIST


item



prev loc


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LINKED LIST


item



prev loc


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LINKED LIST

Deletingthenodecontainingaparticularitem

Void delete_particular_item(int item){ loc=start; prev=start;

while (loc!=null && loc.data!=item){ prev=loc;

loc=loc.link;

}if (prev==start)

{ start=null;

return;

}


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LINKED LIST


item

if (loc!=null)prev.link=loc.link;

else return unsuccessful;

}

2.linked list

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