Circular Doubly Linked List has properties of both doubly linked list and circular linked list in which two consecutive elements are linked or connected by the previous and next pointer and the last node points to the first node by the next pointer and also the first node points to the last node by the previous pointer.
Following is the representation of a Circular doubly linked list node in C/C++:
static class node {
int data;
// pointer to next node
node next;
// pointer to prev node
node prev;
} // This code is contributed by Yash Agarwal(yashagarwal2852002) |
// Structure of the node struct node {
int data;
// Pointer to next node
struct node* next;
// Pointer to previous node
struct node* prev;
}; |
class Node {
int data;
// Pointer to the next node
Node next;
// Pointer to the previous node
Node prev;
} |
class Node:
def __init__( self ):
# Data in the node
self .data = None
# Pointer to the next node
self . next = None
# Pointer to the previous node
self .prev = None
|
public class Node {
public int Data
{
get ;
set ;
}
public Node Next
{
get ;
set ;
}
public Node Prev
{
get ;
set ;
}
} public class DoublyLinkedList {
// The Doubly Linked List can be implemented here.
// You can create instances of Node to build your list.
} |
class Node { constructor(data) {
this .data = data; // Data stored in the node
this .next = null ; // Pointer to the next node
this .prev = null ; // Pointer to the previous node
}
} |
Insertion in Circular Doubly Linked List:
1. Insertion at the end of the list or in an empty list:
A node(Say N) is inserted with data = 5. So, the previous pointer of N points to N and the next pointer of N also points to N. But now start pointer points to the first node of the list.
2. List initially contains some nodes, start points to the first node of the List:
A node(Say M) is inserted with data = 7, so the previous pointer of M points to the last node, the next pointer of M points to the first node and the last node’s next pointer points to this M node, and first node’s previous pointer points to this M node.
Below is the implementation of the above operations:
// Function to insert at the end void insertEnd( struct Node** start, int value)
{ // If the list is empty, create a single node
// circular and doubly list
if (*start == NULL) {
struct Node* new_node = new Node;
new_node->data = value;
new_node->next = new_node->prev = new_node;
*start = new_node;
return ;
}
// If list is not empty
/* Find last node */
Node* last = (*start)->prev;
// Create Node dynamically
struct Node* new_node = new Node;
new_node->data = value;
// Start is going to be next of new_node
new_node->next = *start;
// Make new node previous of start
(*start)->prev = new_node;
// Make last previous of new node
new_node->prev = last;
// Make new node next of old last
last->next = new_node;
} |
// Function to insert at the end static void insertEnd( int value)
{ // If the list is empty, create a single
// node circular and doubly list
if (start == null ) {
Node new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
// Find last node
Node last = (start).prev;
// Create Node dynamically
Node new_node = new Node();
new_node.data = value;
// Start is going to be
// next of new_node
new_node.next = start;
// Make new node previous of start
(start).prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
} // This code is contributed by rutvik_56 |
# Function to insert at the end def insertEnd(value):
global start
# If the list is empty, create a
# single node circular and doubly list
if (start = = None ):
new_node = Node( 0 )
new_node.data = value
new_node. next = new_node.prev = new_node
start = new_node
return
# If list is not empty
# Find last node */
last = (start).prev
# Create Node dynamically
new_node = Node( 0 )
new_node.data = value
# Start is going to be next of new_node
new_node. next = start
# Make new node previous of start
(start).prev = new_node
# Make last previous of new node
new_node.prev = last
# Make new node next of old last
last. next = new_node
# This code is contributed by shivanisinghss2110
|
// Function to insert at the end static void insertEnd( int value)
{ Node new_node;
// If the list is empty, create a single node
// circular and doubly list
if (start == null ) {
new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
/* Find last node */
Node last = (start).prev;
// Create Node dynamically
new_node = new Node();
new_node.data = value;
// Start is going to be next of new_node
new_node.next = start;
// Make new node previous of start
(start).prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
} // This code is contributed by Pratham76 |
// Function to insert at the end function insertEnd(value)
{ // If the list is empty, create a single
// node circular and doubly list
if (start == null )
{
var new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
// Find last node
var last = (start).prev;
// Create Node dynamically
var new_node = new Node();
new_node.data = value;
// Start is going to be
// next of new_node
new_node.next = start;
// Make new node previous of start
(start).prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
} // This code contributed by aashish1995 |
3. Insertion at the beginning of the list:
To insert a node at the beginning of the list, create a node(Say T) with data = 5, T next pointer points to the first node of the list, T previous pointer points to the last node of the list, last node’s next pointer points to this T node, first node’s previous pointer also points this T node and at last don’t forget to shift ‘Start’ pointer to this T node.
Below is the implementation of the above operation:
// Function to insert Node at the beginning // of the List, void insertBegin( struct Node** start, int value)
{ // Pointer points to last Node
struct Node* last = (*start)->prev;
struct Node* new_node = new Node;
new_node->data = value; // Inserting the data
// setting up previous and next of new node
new_node->next = *start;
new_node->prev = last;
// Update next and previous pointers of start
// and last.
last->next = (*start)->prev = new_node;
// Update start pointer
*start = new_node;
} |
// Function to insert Node at the beginning // of the List, static void insertBegin( int value)
{ // Pointer points to last Node
Node last = (start).prev;
Node new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = (start).prev = new_node;
// Update start pointer
start = new_node;
} // this code is contributed by shivanisinghss2110 |
# Function to insert Node at the beginning # of the List, def insertBegin(value):
global start
# Pointer points to last Node
last = (start).prev
new_node = Node( 0 )
new_node.data = value # Inserting the data
# setting up previous and
# next of new node
new_node. next = start
new_node.prev = last
# Update next and previous pointers
# of start and last.
last. next = (start).prev = new_node
# Update start pointer
start = new_node
# This code is contributed by shivanisinghss2110
|
// Function to insert Node at the beginning // of the List, static void insertBegin( int value)
{ // Pointer points to last Node
Node last = (start).prev;
Node new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = (start).prev = new_node;
// Update start pointer
start = new_node;
} // This code is contributed by shivanisinghss2110 |
// Function to insert Node at the beginning // of the List,
function insertBegin(value) {
// Pointer points to last Node
var last = start.prev;
var new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = start.prev = new_node;
// Update start pointer
start = new_node;
}
// This code is contributed by shivanisinghss2110
|
4. Insertion in between the nodes of the list:
To insert a node in between the list, two data values are required one after which new node will be inserted and another is the data of the new node.
Below is the implementation of the above operation:
// Function to insert node with value as value1. // The new node is inserted after the node with // with value2 void insertAfter( struct Node** start, int value1,
int value2)
{ struct Node* new_node = new Node;
new_node->data = value1; // Inserting the data
// Find node having value2 and next node of it
struct Node* temp = *start;
while (temp->data != value2)
temp = temp->next;
struct Node* next = temp->next;
// insert new_node between temp and next.
temp->next = new_node;
new_node->prev = temp;
new_node->next = next;
next->prev = new_node;
} |
// Function to insert node with value as value1. // The new node is inserted after the node with // with value2 static void insertAfter( int value1, int value2)
{ Node new_node = new Node();
new_node.data = value1; // Inserting the data
// Find node having value2 and next node of it
Node temp = start;
while (temp.data != value2)
temp = temp.next;
Node next = temp.next;
// insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
} // this code is contributed by shivanisinghss2110 |
# Function to insert node with value as value1. # The new node is inserted after the node with # with value2 def insertAfter(value1, value2):
global start
new_node = Node( 0 )
new_node.data = value1 # Inserting the data
# Find node having value2 and
# next node of it
temp = start
while (temp.data ! = value2):
temp = temp. next
next = temp. next
# insert new_node between temp and next.
temp. next = new_node
new_node.prev = temp
new_node. next = next
next .prev = new_node
# this code is contributed by shivanisinghss2110 |
// Function to insert node with value as value1. // The new node is inserted after the node with // with value2 static void insertAfter( int value1, int value2)
{ Node new_node = new Node();
new_node.data = value1; // Inserting the data
// Find node having value2 and next node of it
Node temp = start;
while (temp.data != value2)
temp = temp.next;
Node next = temp.next;
// insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
} // this code is contributed by shivanisinghss2110 |
<script> // Function to insert node with value as value1. // The new node is inserted after the node with // with value2 function insertAfter(value1, value2)
{ var new_node = new Node();
// Inserting the data
new_node.data = value1;
// Find node having value2 and
// next node of it
var temp = start;
while (temp.data != value2)
temp = temp.next;
var next = temp.next;
// Insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
} // This code is contributed by shivanisinghss2110 </script> |
Following is a complete program that uses all of the above methods to create a circular doubly linked list.
// C++ program to illustrate inserting a Node in // a Circular Doubly Linked list in begging, end // and middle #include <bits/stdc++.h> using namespace std;
// Structure of a Node struct Node {
int data;
struct Node* next;
struct Node* prev;
}; // Function to insert at the end void insertEnd( struct Node** start, int value)
{ // If the list is empty, create a single node
// circular and doubly list
if (*start == NULL) {
struct Node* new_node = new Node;
new_node->data = value;
new_node->next = new_node->prev = new_node;
*start = new_node;
return ;
}
// If list is not empty
/* Find last node */
Node* last = (*start)->prev;
// Create Node dynamically
struct Node* new_node = new Node;
new_node->data = value;
// Start is going to be next of new_node
new_node->next = *start;
// Make new node previous of start
(*start)->prev = new_node;
// Make last previous of new node
new_node->prev = last;
// Make new node next of old last
last->next = new_node;
} // Function to insert Node at the beginning // of the List, void insertBegin( struct Node** start, int value)
{ // Pointer points to last Node
struct Node* last = (*start)->prev;
struct Node* new_node = new Node;
new_node->data = value; // Inserting the data
// setting up previous and next of new node
new_node->next = *start;
new_node->prev = last;
// Update next and previous pointers of start
// and last.
last->next = (*start)->prev = new_node;
// Update start pointer
*start = new_node;
} // Function to insert node with value as value1. // The new node is inserted after the node with // with value2 void insertAfter( struct Node** start, int value1,
int value2)
{ struct Node* new_node = new Node;
new_node->data = value1; // Inserting the data
// Find node having value2 and next node of it
struct Node* temp = *start;
while (temp->data != value2)
temp = temp->next;
struct Node* next = temp->next;
// insert new_node between temp and next.
temp->next = new_node;
new_node->prev = temp;
new_node->next = next;
next->prev = new_node;
} void display( struct Node* start)
{ struct Node* temp = start;
printf ( "\nTraversal in forward direction \n" );
while (temp->next != start) {
printf ( "%d " , temp->data);
temp = temp->next;
}
printf ( "%d " , temp->data);
printf ( "\nTraversal in reverse direction \n" );
Node* last = start->prev;
temp = last;
while (temp->prev != last) {
printf ( "%d " , temp->data);
temp = temp->prev;
}
printf ( "%d " , temp->data);
} /* Driver program to test above functions*/ int main()
{ /* Start with the empty list */
struct Node* start = NULL;
// Insert 5. So linked list becomes 5->NULL
insertEnd(&start, 5);
// Insert 4 at the beginning. So linked
// list becomes 4->5
insertBegin(&start, 4);
// Insert 7 at the end. So linked list
// becomes 4->5->7
insertEnd(&start, 7);
// Insert 8 at the end. So linked list
// becomes 4->5->7->8
insertEnd(&start, 8);
// Insert 6, after 5. So linked list
// becomes 4->5->6->7->8
insertAfter(&start, 6, 5);
printf ( "Created circular doubly linked list is: " );
display(start);
return 0;
} |
// Java program to illustrate inserting a Node in // a Circular Doubly Linked list in begging, end // and middle import java.util.*;
class GFG {
static Node start;
// Structure of a Node
static class Node {
int data;
Node next;
Node prev;
};
// Function to insert at the end
static void insertEnd( int value)
{
// If the list is empty, create a single node
// circular and doubly list
if (start == null ) {
Node new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
/* Find last node */
Node last = (start).prev;
// Create Node dynamically
Node new_node = new Node();
new_node.data = value;
// Start is going to be next of new_node
new_node.next = start;
// Make new node previous of start
(start).prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
}
// Function to insert Node at the beginning
// of the List,
static void insertBegin( int value)
{
// Pointer points to last Node
Node last = (start).prev;
Node new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = (start).prev = new_node;
// Update start pointer
start = new_node;
}
// Function to insert node with value as value1.
// The new node is inserted after the node with
// with value2
static void insertAfter( int value1, int value2)
{
Node new_node = new Node();
new_node.data = value1; // Inserting the data
// Find node having value2 and next node of it
Node temp = start;
while (temp.data != value2)
temp = temp.next;
Node next = temp.next;
// insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
}
static void display()
{
Node temp = start;
System.out.printf(
"\nTraversal in forward direction \n" );
while (temp.next != start) {
System.out.printf( "%d " , temp.data);
temp = temp.next;
}
System.out.printf( "%d " , temp.data);
System.out.printf(
"\nTraversal in reverse direction \n" );
Node last = start.prev;
temp = last;
while (temp.prev != last) {
System.out.printf( "%d " , temp.data);
temp = temp.prev;
}
System.out.printf( "%d " , temp.data);
}
/* Driver code*/
public static void main(String[] args)
{
/* Start with the empty list */
Node start = null ;
// Insert 5. So linked list becomes 5.null
insertEnd( 5 );
// Insert 4 at the beginning. So linked
// list becomes 4.5
insertBegin( 4 );
// Insert 7 at the end. So linked list
// becomes 4.5.7
insertEnd( 7 );
// Insert 8 at the end. So linked list
// becomes 4.5.7.8
insertEnd( 8 );
// Insert 6, after 5. So linked list
// becomes 4.5.6.7.8
insertAfter( 6 , 5 );
System.out.printf(
"Created circular doubly linked list is: " );
display();
}
} // This code is contributed by Rajput-Ji |
# Python3 program to illustrate inserting # a Node in a Circular Doubly Linked list # in begging, end and middle # Structure of a Node class Node:
def __init__( self , data):
self .data = data
self . next = None
self .prev = None
# Function to insert at the end def insertEnd(value):
global start
# If the list is empty, create a
# single node circular and doubly list
if (start = = None ):
new_node = Node( 0 )
new_node.data = value
new_node. next = new_node.prev = new_node
start = new_node
return
# If list is not empty
# Find last node */
last = (start).prev
# Create Node dynamically
new_node = Node( 0 )
new_node.data = value
# Start is going to be next of new_node
new_node. next = start
# Make new node previous of start
(start).prev = new_node
# Make last previous of new node
new_node.prev = last
# Make new node next of old last
last. next = new_node
# Function to insert Node at the beginning # of the List, def insertBegin(value):
global start
# Pointer points to last Node
last = (start).prev
new_node = Node( 0 )
new_node.data = value # Inserting the data
# setting up previous and
# next of new node
new_node. next = start
new_node.prev = last
# Update next and previous pointers
# of start and last.
last. next = (start).prev = new_node
# Update start pointer
start = new_node
# Function to insert node with value as value1. # The new node is inserted after the node with # with value2 def insertAfter(value1, value2):
global start
new_node = Node( 0 )
new_node.data = value1 # Inserting the data
# Find node having value2 and
# next node of it
temp = start
while (temp.data ! = value2):
temp = temp. next
next = temp. next
# insert new_node between temp and next.
temp. next = new_node
new_node.prev = temp
new_node. next = next
next .prev = new_node
def display():
global start
temp = start
print ( "Traversal in forward direction:" )
while (temp. next ! = start):
print (temp.data, end = " " )
temp = temp. next
print (temp.data)
print ( "Traversal in reverse direction:" )
last = start.prev
temp = last
while (temp.prev ! = last):
print (temp.data, end = " " )
temp = temp.prev
print (temp.data)
# Driver Code if __name__ = = '__main__' :
global start
# Start with the empty list
start = None
# Insert 5. So linked list becomes 5.None
insertEnd( 5 )
# Insert 4 at the beginning. So linked
# list becomes 4.5
insertBegin( 4 )
# Insert 7 at the end. So linked list
# becomes 4.5.7
insertEnd( 7 )
# Insert 8 at the end. So linked list
# becomes 4.5.7.8
insertEnd( 8 )
# Insert 6, after 5. So linked list
# becomes 4.5.6.7.8
insertAfter( 6 , 5 )
print ( "Created circular doubly linked list is: " )
display()
# This code is contributed by Arnab kundu |
// C# program to illustrate inserting a Node in // a Circular Doubly Linked list in begging, end // and middle using System;
using System.Collections.Generic;
class GFG {
static Node start;
// Structure of a Node
public class Node {
public int data;
public Node next;
public Node prev;
};
// Function to insert at the end
static void insertEnd( int value)
{
Node new_node;
// If the list is empty, create a single node
// circular and doubly list
if (start == null ) {
new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
/* Find last node */
Node last = (start).prev;
// Create Node dynamically
new_node = new Node();
new_node.data = value;
// Start is going to be next of new_node
new_node.next = start;
// Make new node previous of start
(start).prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
}
// Function to insert Node at the beginning
// of the List,
static void insertBegin( int value)
{
// Pointer points to last Node
Node last = (start).prev;
Node new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = (start).prev = new_node;
// Update start pointer
start = new_node;
}
// Function to insert node with value as value1.
// The new node is inserted after the node with
// with value2
static void insertAfter( int value1, int value2)
{
Node new_node = new Node();
new_node.data = value1; // Inserting the data
// Find node having value2 and next node of it
Node temp = start;
while (temp.data != value2)
temp = temp.next;
Node next = temp.next;
// insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
}
static void display()
{
Node temp = start;
Console.Write(
"\nTraversal in forward direction \n" );
while (temp.next != start) {
Console.Write( "{0} " , temp.data);
temp = temp.next;
}
Console.Write( "{0} " , temp.data);
Console.Write(
"\nTraversal in reverse direction \n" );
Node last = start.prev;
temp = last;
while (temp.prev != last) {
Console.Write( "{0} " , temp.data);
temp = temp.prev;
}
Console.Write( "{0} " , temp.data);
}
/* Driver code*/
public static void Main(String[] args)
{
/* Start with the empty list */
Node start = null ;
// Insert 5. So linked list becomes 5.null
insertEnd(5);
// Insert 4 at the beginning. So linked
// list becomes 4.5
insertBegin(4);
// Insert 7 at the end. So linked list
// becomes 4.5.7
insertEnd(7);
// Insert 8 at the end. So linked list
// becomes 4.5.7.8
insertEnd(8);
// Insert 6, after 5. So linked list
// becomes 4.5.6.7.8
insertAfter(6, 5);
Console.Write(
"Created circular doubly linked list is: " );
display();
}
} // This code is contributed by Rajput-Ji |
// JavaScript program to illustrate inserting a Node in // a Circular Doubly Linked list in begging, end // and middle var start = null ;
// Structure of a Node class Node { constructor() {
this .data = 0;
this .next = null ;
this .prev = null ;
}
} // Function to insert at the end function insertEnd(value) {
var new_node;
// If the list is empty, create a single node
// circular and doubly list
if (start == null ) {
new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return ;
}
// If list is not empty
/* Find last node */
var last = start.prev;
// Create Node dynamically
new_node = new Node();
new_node.data = value;
// Start is going to be next of new_node
new_node.next = start;
// Make new node previous of start
start.prev = new_node;
// Make last previous of new node
new_node.prev = last;
// Make new node next of old last
last.next = new_node;
} // Function to insert Node at the beginning // of the List, function insertBegin(value) {
// Pointer points to last Node
var last = start.prev;
var new_node = new Node();
new_node.data = value; // Inserting the data
// setting up previous and next of new node
new_node.next = start;
new_node.prev = last;
// Update next and previous pointers of start
// and last.
last.next = start.prev = new_node;
// Update start pointer
start = new_node;
} // Function to insert node with value as value1. // The new node is inserted after the node with // with value2 function insertAfter(value1, value2) {
var new_node = new Node();
new_node.data = value1; // Inserting the data
// Find node having value2 and next node of it
var temp = start;
while (temp.data != value2) temp = temp.next;
var next = temp.next;
// insert new_node between temp and next.
temp.next = new_node;
new_node.prev = temp;
new_node.next = next;
next.prev = new_node;
} function display() {
var temp = start;
document.write( "<br>Traversal in forward direction <br>" );
while (temp.next != start) {
document.write(temp.data + " " );
temp = temp.next;
}
document.write(temp.data);
document.write( "<br>Traversal in reverse direction <br>" );
var last = start.prev;
temp = last;
while (temp.prev != last) {
document.write(temp.data + " " );
temp = temp.prev;
}
document.write(temp.data);
} /* Driver code*/ /* Start with the empty list */ var start = null ;
// Insert 5. So linked list becomes 5.null insertEnd(5); // Insert 4 at the beginning. So linked // list becomes 4.5 insertBegin(4); // Insert 7 at the end. So linked list // becomes 4.5.7 insertEnd(7); // Insert 8 at the end. So linked list // becomes 4.5.7.8 insertEnd(8); // Insert 6, after 5. So linked list // becomes 4.5.6.7.8 insertAfter(6, 5); document.write( "Created circular doubly linked list is: " );
display(); |
Created circular doubly linked list is: Traversal in forward direction 4 5 6 7 8 Traversal in reverse direction 8 7 6 5 4
Time Complexity: O(N)
Auxiliary Space: O(1), As constant extra space is used.
Advantages of circular doubly linked list:
- The list can be traversed from both directions i.e. from head to tail or from tail to head.
- Jumping from head to tail or from tail to head is done in constant time O(1).
- Circular Doubly Linked Lists are used for the implementation of advanced data structures like the Fibonacci Heap.
Disadvantages of circular doubly linked list:
- It takes slightly extra memory in each node to accommodate the previous pointer.
- Lots of pointers are involved while implementing or doing operations on a list. So, pointers should be handled carefully otherwise data of the list may get lost.
Applications of Circular doubly linked list:
- Managing song playlists in media player applications.
- Managing shopping carts in online shopping.
This article is contributed by Akash Gupta.