Pre-requisite: Convert an Array to a Circular Doubly Linked List, Doubly Circular Linked List
Given a doubly circular linked list. The task is to find the position of an element in the list.
Image Representation:
Algorithm:
- Declare a temp pointer, and initialize it to the head of the list.
- Iterate the loop until temp reaches the start address (last node in the list, as it is in a circular fashion), and check for the n element, whether present or not.
- If it is present, raise a flag, increment count, and break the loop.
- At the last, as the last node is not visited yet check for the n element if present does step 3.
The below program illustrates the above approach:
// 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 a node at the end
void insertNode(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 display the
// circular doubly linked list
void displayList(struct Node* start)
{
struct Node *temp = start;
while (temp->next != start)
{
printf("%d ", temp->data);
temp = temp->next;
}
printf("%d ", temp->data);
}
// Function to search the particular element
// from the list
int searchList(struct Node* start, int search)
{
// Declare the temp variable
struct Node *temp = start;
// Declare other control
// variable for the searching
int count=0,flag=0,value;
// If start is NULL return -1
if(temp == NULL)
return -1;
else
{
// Move the temp pointer until,
// temp->next doesn't move
// start address (Circular Fashion)
while(temp->next != start)
{
// Increment count for location
count++;
// If it is found raise the
// flag and break the loop
if(temp->data == search)
{
flag = 1;
count--;
break;
}
// Increment temp pointer
temp = temp->next;
}
// Check whether last element in the
// list content the value if contain,
// raise a flag and increment count
if(temp->data == search)
{
count++;
flag = 1;
}
// If flag is true, then element
// found, else not
if(flag == 1)
cout<<"\n"<<search <<" found at location "<<
count<<endl;
else
cout<<"\n"<<search <<" not found"<<endl;
}
}
// Driver code
int main()
{
/* Start with the empty list */
struct Node* start = NULL;
// Insert 4. So linked list becomes 4->NULL
insertNode(&start, 4);
// Insert 5. So linked list becomes 4->5
insertNode(&start, 5);
// Insert 7. So linked list
// becomes 4->5->7
insertNode(&start, 7);
// Insert 8. So linked list
// becomes 4->5->7->8
insertNode(&start, 8);
// Insert 6. So linked list
// becomes 4->5->7->8->6
insertNode(&start, 6);
printf("Created circular doubly linked list is: ");
displayList(start);
searchList(start, 5);
return 0;
}
// Java program to illustrate inserting
// a Node in a Circular Doubly Linked list
// in begging, end and middle
class GFG
{
// Structure of a Node
static class Node
{
int data;
Node next;
Node prev;
};
// Function to insert a node at the end
static Node insertNode(Node start, 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 new_node;
}
// 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;
return start;
}
// Function to display the
// circular doubly linked list
static void displayList(Node start)
{
Node temp = start;
while (temp.next != start)
{
System.out.printf("%d ", temp.data);
temp = temp.next;
}
System.out.printf("%d ", temp.data);
}
// Function to search the particular element
// from the list
static int searchList(Node start, int search)
{
// Declare the temp variable
Node temp = start;
// Declare other control
// variable for the searching
int count = 0, flag = 0, value;
// If start is null return -1
if(temp == null)
return -1;
else
{
// Move the temp pointer until,
// temp.next doesn't move
// start address (Circular Fashion)
while(temp.next != start)
{
// Increment count for location
count++;
// If it is found raise the
// flag and break the loop
if(temp.data == search)
{
flag = 1;
count--;
break;
}
// Increment temp pointer
temp = temp.next;
}
// Check whether last element in the
// list content the value if contain,
// raise a flag and increment count
if(temp.data == search)
{
count++;
flag = 1;
}
// If flag is true, then element
// found, else not
if(flag == 1)
System.out.println("\n"+search +" found at location "+
count);
else
System.out.println("\n"+search +" not found");
}
return -1;
}
// Driver code
public static void main(String args[])
{
// Start with the empty list /
Node start = null;
// Insert 4. So linked list becomes 4.null
start= insertNode(start, 4);
// Insert 5. So linked list becomes 4.5
start= insertNode(start, 5);
// Insert 7. So linked list
// becomes 4.5.7
start= insertNode(start, 7);
// Insert 8. So linked list
// becomes 4.5.7.8
start= insertNode(start, 8);
// Insert 6. So linked list
// becomes 4.5.7.8.6
start= insertNode(start, 6);
System.out.printf("Created circular doubly linked list is: ");
displayList(start);
searchList(start, 5);
}
}
// This code is contributed by Arnab Kundu
# Python3 program to illustrate inserting a Node in
# a Circular Doubly Linked list in begging, end
# and middle
import math
# Structure of a Node
class Node:
def __init__(self, data):
self.data = data
self.next = None
# Function to insert a node at the end
def insertNode(start, value):
# If the list is empty, create a single node
# circular and doubly list
if (start == None) :
new_node = Node(value)
new_node.data = value
new_node.next = new_node
new_node.prev = new_node
start = new_node
return new_node
# If list is not empty
# Find last node */
last = start.prev
# Create Node dynamically
new_node = Node(value)
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
return start
# Function to display the
# circular doubly linked list
def displayList(start):
temp = start
while (temp.next != start):
print(temp.data, end = " ")
temp = temp.next
print(temp.data)
# Function to search the particular element
# from the list
def searchList(start, search):
# Declare the temp variable
temp = start
# Declare other control
# variable for the searching
count = 0
flag = 0
value = 0
# If start is None return -1
if(temp == None):
return -1
else:
# Move the temp pointer until,
# temp.next doesn't move
# start address (Circular Fashion)
while(temp.next != start):
# Increment count for location
count = count + 1
# If it is found raise the
# flag and break the loop
if(temp.data == search):
flag = 1
count = count - 1
break
# Increment temp pointer
temp = temp.next
# Check whether last element in the
# list content the value if contain,
# raise a flag and increment count
if(temp.data == search):
count = count + 1
flag = 1
# If flag is true, then element
# found, else not
if(flag == 1):
print(search,"found at location ", count)
else:
print(search, " not found")
return -1
# Driver code
if __name__=='__main__':
# Start with the empty list */
start = None
# Insert 4. So linked list becomes 4.None
start = insertNode(start, 4)
# Insert 5. So linked list becomes 4.5
start = insertNode(start, 5)
# Insert 7. So linked list
# becomes 4.5.7
start = insertNode(start, 7)
# Insert 8. So linked list
# becomes 4.5.7.8
start = insertNode(start, 8)
# Insert 6. So linked list
# becomes 4.5.7.8.6
start = insertNode(start, 6)
print("Created circular doubly linked list is: ",
end = "")
displayList(start)
searchList(start, 5)
# This article contributed by Srathore
// C# Program to Reverse a List using Data Swapping
using System;
class GFG
{
// Structure of a Node
public class Node
{
public int data;
public Node next;
public Node prev;
};
// Function to insert a node at the end
static Node insertNode(Node start, int value)
{
// If the list is empty, create a single node
// circular and doubly list
Node new_node = new Node();
if (start == null)
{
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return new_node;
}
// 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;
return start;
}
// Function to display the
// circular doubly linked list
static void displayList(Node start)
{
Node temp = start;
while (temp.next != start)
{
Console.Write("{0} ", temp.data);
temp = temp.next;
}
Console.Write("{0} ", temp.data);
}
// Function to search the particular element
// from the list
static int searchList(Node start, int search)
{
// Declare the temp variable
Node temp = start;
// Declare other control
// variable for the searching
int count = 0, flag = 0, value;
// If start is null return -1
if(temp == null)
return -1;
else
{
// Move the temp pointer until,
// temp.next doesn't move
// start address (Circular Fashion)
while(temp.next != start)
{
// Increment count for location
count++;
// If it is found raise the
// flag and break the loop
if(temp.data == search)
{
flag = 1;
count--;
break;
}
// Increment temp pointer
temp = temp.next;
}
// Check whether last element in the
// list content the value if contain,
// raise a flag and increment count
if(temp.data == search)
{
count++;
flag = 1;
}
// If flag is true, then element
// found, else not
if(flag == 1)
Console.WriteLine("\n"+search +" found at location "+
count);
else
Console.WriteLine("\n"+search +" not found");
}
return -1;
}
// Driver code
public static void Main(String []args)
{
// Start with the empty list /
Node start = null;
// Insert 4. So linked list becomes 4.null
start= insertNode(start, 4);
// Insert 5. So linked list becomes 4.5
start= insertNode(start, 5);
// Insert 7. So linked list
// becomes 4.5.7
start= insertNode(start, 7);
// Insert 8. So linked list
// becomes 4.5.7.8
start= insertNode(start, 8);
// Insert 6. So linked list
// becomes 4.5.7.8.6
start= insertNode(start, 6);
Console.Write("Created circular doubly linked list is: ");
displayList(start);
searchList(start, 5);
}
}
// This code has been contributed by 29AjayKumar
<script>
// JavaScript program to illustrate inserting
// a Node in a Circular Doubly Linked list
// in begging, end and middle
class Node
{
constructor()
{
this.data=0;
this.next=this.prev=null;
}
}
// Function to insert a node at the end
function insertNode(start,value)
{
// If the list is empty, create a single node
// circular and doubly list
if (start == null)
{
let new_node = new Node();
new_node.data = value;
new_node.next = new_node.prev = new_node;
start = new_node;
return new_node;
}
// If list is not empty
// Find last node /
let last = (start).prev;
// Create Node dynamically
let 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;
return start;
}
// Function to display the
// circular doubly linked list
function displayList(start)
{
let temp = start;
while (temp.next != start)
{
document.write(temp.data+" ");
temp = temp.next;
}
document.write(temp.data+" ");
}
// Function to search the particular element
// from the list
function searchList(start,search)
{
// Declare the temp variable
let temp = start;
// Declare other control
// variable for the searching
let count = 0, flag = 0, value;
// If start is null return -1
if(temp == null)
return -1;
else
{
// Move the temp pointer until,
// temp.next doesn't move
// start address (Circular Fashion)
while(temp.next != start)
{
// Increment count for location
count++;
// If it is found raise the
// flag and break the loop
if(temp.data == search)
{
flag = 1;
count--;
break;
}
// Increment temp pointer
temp = temp.next;
}
// Check whether last element in the
// list content the value if contain,
// raise a flag and increment count
if(temp.data == search)
{
count++;
flag = 1;
}
// If flag is true, then element
// found, else not
if(flag == 1)
document.write("<br>"+search +" found at location "+
count);
else
document.write("<br>"+search +" not found");
}
return -1;
}
// Driver code
// Start with the empty list /
let start = null;
// Insert 4. So linked list becomes 4.null
start= insertNode(start, 4);
// Insert 5. So linked list becomes 4.5
start= insertNode(start, 5);
// Insert 7. So linked list
// becomes 4.5.7
start= insertNode(start, 7);
// Insert 8. So linked list
// becomes 4.5.7.8
start= insertNode(start, 8);
// Insert 6. So linked list
// becomes 4.5.7.8.6
start= insertNode(start, 6);
document.write("Created circular doubly linked list is: ");
displayList(start);
searchList(start, 5);
// This code is contributed by avanitrachhadiya2155
</script>
Output:
Created circular doubly linked list is: 4 5 7 8 6 5 found at location 2
Time Complexity: O(n), as we are using a loop to traverse n times. Where n is the number of nodes in the linked list.
Auxiliary Space: O(1), as we are not using any extra space.