Deletion at different positions in a Circular Linked List
Last Updated :
13 Apr, 2023
tGiven a Circular Linked List. The task is to write programs to delete nodes from this list present at:
- First position.
- Last Position.
- At any given position i .
Deleting first node from Singly Circular Linked List
Examples:
Input : 99->11->22->33->44->55->66
Output : 11->22->33->44->55->66
Input : 11->22->33->44->55->66
Output : 22->33->44->55->66
Deleting First Node from Circular Linked List
Approach:
- Take two pointers current and previous and traverse the list.
- Keep the pointer current fixed pointing to the first node and move previous until it reaches the last node.
- Once, the pointer previous reaches the last node, do the following:
- previous->next = current-> next
- head = previous -> next;
Implementation: Function to delete first node from singly circular linked list.
C++
// Function to delete First node of
// Circular Linked List
void DeleteFirst(struct Node** head)
{
struct Node *previous = *head, *firstNode = *head;
// check if list doesn't have any node
// if not then return
if (*head == NULL) {
printf("\nList is empty\n");
return;
}
// check if list have single node
// if yes then delete it and return
if (previous->next == previous) {
*head = NULL;
return;
}
// traverse second node to first
while (previous->next != *head) {
previous = previous->next;
}
// now previous is last node and
// first node(firstNode) link address
// put in last node(previous) link
previous->next = firstNode->next;
// make second node as head node
*head = previous->next;
free(firstNode);
return;
}
// Function to delete First node of
// Circular Linked List
static void DeleteFirst(Node head)
{
Node previous = head, firstNode = head;
// Check if list doesn't have any node
// if not then return
if (head == null)
{
System.out.printf("\nList is empty\n");
return;
}
// Check if list have single node
// if yes then delete it and return
if (previous.next == previous)
{
head = null;
return;
}
// Traverse second node to first
while (previous.next != head)
{
previous = previous.next;
}
// Now previous is last node and
// first node(firstNode) link address
// put in last node(previous) link
previous.next = firstNode.next;
// Make second node as head node
head = previous.next;
System.gc();
return;
}
// This code is contributed by aashish1995
# Function delete First node of
# Circular Linked List
def DeleteFirst(head):
previous = head
next = head
# check list have any node
# if not then return
if (head == None) :
print("\nList is empty")
return None
# check list have single node
# if yes then delete it and return
if (previous.next == previous) :
head = None
return None
# traverse second to first
while (previous.next != head):
previous = previous.next
next = previous.next
# now previous is last node and
# next is first node of list
# first node(next) link address
# put in last node(previous) link
previous.next = next.next
# make second node as head node
head = previous.next
return head
# This code is contributed by shivanisinghss2110
using System;
public class GFG{
static public// Function delete First node of
// Circular Linked List
static Node DeleteFirst(Node head)
{
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null)
{
Console.Write("\nList is empty\n");
return null;
}
// Check if list have single node
// if yes then delete it and return
if (previous.next == previous)
{
head = null;
return null;
}
// Traverse second node to first
while (previous.next != head)
{
previous = previous.next;
next = previous.next;
}
// Now previous is last node and
// first node(firstNode) link address
// put in last node(previous) link
previous.next = next.next;
// Make second node as head node
head = previous.next;
return head;
}
// This code is contributed by shivanisinghss2110.
c void Main (){
// Code
}
<script>
function DeleteFirst(head)
{
previous = head, firstNode = head;
// Check if list doesn't have any node
// if not then return
if (head == null)
{
document.write("<br>List is empty<br>");
return;
}
// Check if list have single node
// if yes then delete it and return
if (previous.next == previous)
{
head = null;
return;
}
// Traverse second node to first
while (previous.next != head)
{
previous = previous.next;
}
// Now previous is last node and
// first node(firstNode) link address
// put in last node(previous) link
previous.next = firstNode.next;
// Make second node as head node
head = previous.next;
return;
}
// This code is contributed by rag2127
</script>
Time Complexity: O(N), where N is the number of nodes in the Linked List.
Auxiliary Space: O(1)
Deleting the last node of the Circular Linked List
Examples:
Input : 99->11->22->33->44->55->66
Output : 99->11->22->33->44->55
Input : 99->11->22->33->44->55
Output : 99->11->22->33->44
Delete last node from Circular Linked List
Approach:
- Take two pointers current and previous and traverse the list.
- Move both pointers such that next of previous is always pointing to current. Keep moving the pointers current and previous until current reaches the last node and previous is at the second last node.
- Once, the pointer current reaches the last node, do the following:
- previous->next = current-> next
- head = previous -> next;
Function to delete last node from the list:
C++
// Function delete last node of
// Circular Linked List
void DeleteLast(struct Node** head)
{
struct Node *current = *head, *temp = *head, *previous;
// check if list doesn't have any node
// if not then return
if (*head == NULL) {
printf("\nList is empty\n");
return;
}
// check if list have single node
// if yes then delete it and return
if (current->next == current) {
*head = NULL;
return;
}
// move first node to last
// previous
while (current->next != *head) {
previous = current;
current = current->next;
}
previous->next = current->next;
*head = previous->next;
free(current);
return;
}
// Function to delete last node of
// Circular Linked List
static Node DeleteLast(Node head)
{
Node current = head, temp = head, previous = null;
// Check if list doesn't have any node
// if not then return
if (head == null)
{
System.out.printf("\nList is empty\n");
return null;
}
// Check if list have single node
// if yes then delete it and return
if (current.next == current)
{
head = null;
return null;
}
// Move first node to last
// previous
while (current.next != head)
{
previous = current;
current = current.next;
}
previous.next = current.next;
head = previous.next;
return head;
}
// This code is contributed by pratham76
# Function to delete last node of
# Circular Linked List
def DeleteLast(head):
current = head
temp = head
previous = None
# check if list doesn't have any node
# if not then return
if (head == None):
print("\nList is empty")
return None
# check if list have single node
# if yes then delete it and return
if (current.next == current):
head = None
return None
# move first node to last
# previous
while (current.next != head):
previous = current
current = current.next
previous.next = current.next
head = previous.next
return head
# This code is contributed by rutvik_56
// Function to delete last node of
// Circular Linked List
static Node DeleteLast(Node head)
{
Node current = head, temp = head, previous = null;
// check if list doesn't have any node
// if not then return
if (head == null)
{
Console.Write("\nList is empty\n");
return null;
}
// check if list have single node
// if yes then delete it and return
if (current.next == current)
{
head = null;
return null;
}
// move first node to last
// previous
while (current.next != head)
{
previous = current;
current = current.next;
}
previous.next = current.next;
head = previous.next;
return head;
}
// This code is contributed by shivanisinghss2110
<script>
function DeleteLast(head)
{
let current = head, temp = head, previous = null;
// Check if list doesn't have any node
// if not then return
if (head == null)
{
document.write("<br>List is empty<br>");
return null;
}
// Check if list have single node
// if yes then delete it and return
if (current.next == current)
{
head = null;
return null;
}
// Move first node to last
// previous
while (current.next != head)
{
previous = current;
current = current.next;
}
previous.next = current.next;
head = previous.next;
return head;
}
// This code is contributed by avanitrachhadiya2155
</script>
Time Complexity: O(N) where N is the number of nodes in given Linked List.
Auxiliary Space: O(1)
Deleting nodes at given index in the Circular linked list
Examples:
Input : 99->11->22->33->44->55->66
Index= 4
Output : 99->11->22->33->55->66
Input : 99->11->22->33->44->55->66
Index= 2
Output : 99->11->33->44->55->66
Note: 0-based indexing is considered for the list.
Approach:
- First, find the length of the list. That is, the number of nodes in the list.
- Take two pointers previous and current to traverse the list. Such that previous is one position behind the current node.
- Take a variable count initialized to 0 to keep track of the number of nodes traversed.
- Traverse the list until the given index is reached.
- Once the given index is reached, do previous->next = current->next.
Function to delete a node at given index or location from singly circular linked list:
C++
// Function to delete node at given index
// of Circular Linked List
void DeleteAtPosition(Node* head, int index)
{
// find length of list
int len = Length(head);
int count = 1;
Node* previous = head;
Node* next = head;
// check if list doesn't have any node
// if not then return
if(head == NULL){
cout<<"Delete Last list is empty";
return;
}
// given index is in list or not
if(index >= len || index<0){
cout<<"Index is not Found";
return;
}
// delete first node
if(index == 0){
DeleteFirst(head);
return;
}
// traverse first to last node
while(len > 0){
// if index found delete that node
if(index == count){
previous->next = next->next;
free(next);
return;
}
previous = previous->next;
next = previous->next;
len--;
count++;
}
return;
}
// This code is contributed by Yash Agarwal(yashagarwal2852002)
// Function to delete node at given index
// of Circular Linked List
void DeleteAtPosition(struct Node** head, int index)
{
// find length of list
int len = Length(*head);
int count = 1;
struct Node *previous = *head, *next = *head;
// check if list doesn't have any node
// if not then return
if (*head == NULL) {
printf("\nDelete Last List is empty\n");
return;
}
// given index is in list or not
if (index >= len || index < 0) {
printf("\nIndex is not Found\n");
return;
}
// delete first node
if (index == 0) {
DeleteFirst(head);
return;
}
// traverse first to last node
while (len > 0) {
// if index found delete that node
if (index == count) {
previous->next = next->next;
free(next);
return;
}
previous = previous->next;
next = previous->next;
len--;
count++;
}
return;
}
// Java program to delete node at different
// Function delete node at a given position
// of Circular Linked List
static Node DeleteAtPosition( Node head, int index)
{
// Find length of list
int len = Length(head);
int count = 1;
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null)
{
System.out.printf("\nDelete Last List is empty\n");
return null;
}
// given index is in list or not
if (index >= len || index < 0)
{
System.out.printf("\nIndex is not Found\n");
return null;
}
// delete first node
if (index == 0)
{
head = DeleteFirst(head);
return head;
}
// traverse first to last node
while (len > 0)
{
// if index found delete that node
if (index == count)
{
previous.next = next.next;
return head;
}
previous = previous.next;
next = previous.next;
len--;
count++;
}
return head;
}
// This code is contributed by shivanisinghss2110
# Function delete node at a given position
# of Circular Linked List
def DeleteAtPosition(head, index):
# Find length of list
len = Length(head)
count = 1
previous = head
next = head
# check list have any node
# if not then return
if (head == None):
print("\nDelete Last List is empty")
return None
# given index is in list or not
if (index >= len or index < 0) :
print("\nIndex is not Found")
return None
# delete first node
if (index == 0) :
head = DeleteFirst(head)
return head
# traverse first to last node
while (len > 0):
# if index found delete that node
if (index == count):
previous.next = next.next
return head
previous = previous.next
next = previous.next
len = len - 1
count = count + 1
return head
# This code is contributed by shivanisinghss2110
// C# program to delete node at given index
// of circular linked list
static void DeleteAtPosition(Node head, int index)
{
// find length of list
int len = Length(head);
int count = 1;
Node previous = head;
Node next = head;
// check if list doesn't have any node
// if noth then return
if (head == null) {
Console.Write("Delete Last list is empty");
return;
}
// given index is in list or not
if (index >= len || index < 0) {
Console.Write("Index is not Found");
return;
}
// delete first node
if (index == 0) {
DeleteFirst(head);
return;
}
// traverse first to last node
while (len > 0) {
// if index found delete that node
if (index == count) {
previous.next = next.next;
return;
}
previous = previous.next;
next = previous.next;
len -= 1;
count++;
}
}
// this code is contributed by Kirti
// Agarwal(kirtiagarwal23121999)
<script>
// Function delete node at a given position
// of Circular Linked List
function DeleteAtPosition(head, index){
// Find length of list
let len = head.length
let count = 1
let previous = head
let next = head
// check list have any node
// if not then return
if (head == null){
document.write("</br>","Delete Last List is empty")
return null
}
// given index is in list or not
if (index >= len || index < 0){
document.write("</br>","Index is not Found")
return null
}
// delete first node
if (index == 0){
head = DeleteFirst(head)
return head
}
// traverse first to last node
while (len > 0){
// if index found delete that node
if (index == count){
previous.next = next.next
return head
}
previous = previous.next
next = previous.next
len = len - 1
count = count + 1
}
return head
}
// This code is contributed by shinjanpatra
</script>
Time Complexity: O(N)
Auxiliary Space: O(1)
Program implementing all of the above three functions
C++
// C++ program to delete node at different
// positions from a circular linked list
#include <bits/stdc++.h>
using namespace std;
// structure for a node
struct Node {
int data;
struct Node* next;
};
// Function to insert a node at the end of
// a Circular linked list
void Insert(struct Node** head, int data)
{
struct Node* current = *head;
// Create a new node
struct Node* newNode = new Node;
// check node is created or not
if (!newNode) {
printf("\nMemory Error\n");
return;
}
// insert data into newly created node
newNode->data = data;
// check list is empty
// if not have any node then
// make first node it
if (*head == NULL) {
newNode->next = newNode;
*head = newNode;
return;
}
// if list have already some node
else {
// move first node to last node
while (current->next != *head) {
current = current->next;
}
// put first or head node address
// in new node link
newNode->next = *head;
// put new node address into last
// node link(next)
current->next = newNode;
}
}
// Function print data of list
void Display(struct Node* head)
{
struct Node* current = head;
// if list is empty, simply show message
if (head == NULL) {
printf("\nDisplay List is empty\n");
return;
}
// traverse first to last node
else {
do {
printf("%d ", current->data);
current = current->next;
} while (current != head);
}
}
// Function return number of nodes present in list
int Length(struct Node* head)
{
struct Node* current = head;
int count = 0;
// if list is empty simply return length zero
if (head == NULL) {
return 0;
}
// traverse first to last node
else {
do {
current = current->next;
count++;
} while (current != head);
}
return count;
}
// Function delete First node of Circular Linked List
void DeleteFirst(struct Node** head)
{
struct Node *previous = *head, *next = *head;
// check list have any node
// if not then return
if (*head == NULL) {
printf("\nList is empty\n");
return;
}
// check list have single node
// if yes then delete it and return
if (previous->next == previous) {
*head = NULL;
return;
}
// traverse second to first
while (previous->next != *head) {
previous = previous->next;
next = previous->next;
}
// now previous is last node and
// next is first node of list
// first node(next) link address
// put in last node(previous) link
previous->next = next->next;
// make second node as head node
*head = previous->next;
free(next);
return;
}
// Function to delete last node of
// Circular Linked List
void DeleteLast(struct Node** head)
{
struct Node *current = *head, *temp = *head, *previous;
// check if list doesn't have any node
// if not then return
if (*head == NULL) {
printf("\nList is empty\n");
return;
}
// check if list have single node
// if yes then delete it and return
if (current->next == current) {
*head = NULL;
return;
}
// move first node to last
// previous
while (current->next != *head) {
previous = current;
current = current->next;
}
previous->next = current->next;
*head = previous->next;
free(current);
return;
}
// Function delete node at a given position
// of Circular Linked List
void DeleteAtPosition(struct Node** head, int index)
{
// Find length of list
int len = Length(*head);
int count = 1;
struct Node *previous = *head, *next = *head;
// check list have any node
// if not then return
if (*head == NULL) {
printf("\nDelete Last List is empty\n");
return;
}
// given index is in list or not
if (index >= len || index < 0) {
printf("\nIndex is not Found\n");
return;
}
// delete first node
if (index == 0) {
DeleteFirst(head);
return;
}
// traverse first to last node
while (len > 0) {
// if index found delete that node
if (index == count) {
previous->next = next->next;
free(next);
return;
}
previous = previous->next;
next = previous->next;
len--;
count++;
}
return;
}
// Driver Code
int main()
{
struct Node* head = NULL;
Insert(&head, 99);
Insert(&head, 11);
Insert(&head, 22);
Insert(&head, 33);
Insert(&head, 44);
Insert(&head, 55);
Insert(&head, 66);
// Deleting Node at position
printf("Initial List: ");
Display(head);
printf("\nAfter Deleting node at index 4: ");
DeleteAtPosition(&head, 4);
Display(head);
// Deleting first Node
printf("\n\nInitial List: ");
Display(head);
printf("\nAfter Deleting first node: ");
DeleteFirst(&head);
Display(head);
// Deleting last Node
printf("\n\nInitial List: ");
Display(head);
printf("\nAfter Deleting last node: ");
DeleteLast(&head);
Display(head);
return 0;
}
// Java implementation to delete node at different
// positions from a circular linked list
import java.util.*;
public class GFG {
// structure for a node
static class Node {
int data;
Node next;
};
// Function to insert a node at the end of
// a Circular linked list
static Node Insert(Node head, int data){
Node current = head;
// Create a new node
Node newNode = new Node();
// check node is created or not
if (newNode == null) {
System.out.printf("\nMemory Error\n");
return null;
}
// insert data into newly created node
newNode.data = data;
// check list is empty
// if not have any node then
// make first node it
if (head == null) {
newNode.next = newNode;
head = newNode;
return head;
} else {
// move first node to last node
while (current.next != head) {
current = current.next;
}
// put first or head node address
// in new node link
newNode.next = head;
// put new node address into last
// node link(next)
current.next = newNode;
}
return head;
}
// function to print the data of linked list
static void Display(Node head){
Node current = head;
// if list is empty, simply show message
if (head == null) {
System.out.printf("\nDisplay List is empty\n");
return;
} else {
do {
System.out.printf("%d ", current.data);
current = current.next;
} while (current != head);
}
}
// returns the number of nodes present in the linked list
static int Length(Node head){
Node current = head;
int count = 0;
// if list is empty
// simply return length zero
if (head == null)
return 0;
else {
do {
current = current.next;
count++;
} while (current != head);
}
return count;
}
// function to delete First node of
// circular Linked List
static Node DeleteFirst(Node head){
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null) {
System.out.printf("\nList is empty\n");
return null;
}
// check list have single node
// if yes then delete it and return
if (previous.next == previous) {
head = null;
return null;
}
// traverse second to first
while (previous.next != head) {
previous = previous.next;
next = previous.next;
}
// now previous is last node and
// next is first node of list
// first node(next) link address
// put in last node(previous) link
previous.next = next.next;
// make second node as head node
head = previous.next;
return head;
}
// Function to delete last node of
// Circular Linked List
static Node DeleteLast(Node head){
Node current = head, temp = head, previous = null;
// check if list doesn't have any node
// if not then return
if (head == null) {
System.out.printf("\nList is empty\n");
return null;
}
// check if list have single node
// if yes then delete it and return
if (current.next == current) {
head = null;
return null;
}
// move first node to last
// previous
while (current.next != head) {
previous = current;
current = current.next;
}
previous.next = current.next;
head = previous.next;
return head;
}
// Function delete node at a given position
// of Circular Linked List
static Node DeleteAtPosition(Node head, int index){
// Find length of list
int len = Length(head);
int count = 1;
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null) {
System.out.printf(
"\nDelete Last List is empty\n");
return null;
}
// given index is in list or not
if (index >= len || index < 0) {
System.out.printf("\nIndex is not Found\n");
return null;
}
// delete first node
if (index == 0) {
head = DeleteFirst(head);
return head;
}
// traverse first to last node
while (len > 0) {
// if index found delete that node
if (index == count) {
previous.next = next.next;
return head;
}
previous = previous.next;
next = previous.next;
len--;
count++;
}
return head;
}
// Driver Code
public static void main(String args[])
{
Node head = null;
head = Insert(head, 99);
head = Insert(head, 11);
head = Insert(head, 22);
head = Insert(head, 33);
head = Insert(head, 44);
head = Insert(head, 55);
head = Insert(head, 66);
// Deleting Node at position
System.out.printf("Initial List: ");
Display(head);
System.out.printf(
"\nAfter Deleting node at index 4: ");
head = DeleteAtPosition(head, 4);
Display(head);
// Deleting first Node
System.out.printf("\n\nInitial List: ");
Display(head);
System.out.printf("\nAfter Deleting first node: ");
head = DeleteFirst(head);
Display(head);
// Deleting last Node
System.out.printf("\n\nInitial List: ");
Display(head);
System.out.printf("\nAfter Deleting last node: ");
head = DeleteLast(head);
Display(head);
}
}
// THIS CODE IS CONTRIBUTED BY YASH AGARWAL(YASHAGARWAL2852002)
# Python3 program to delete node at different
# positions from a circular linked list
# A linked list node
class Node:
def __init__(self, new_data):
self.data = new_data
self.next = None
self.prev = None
# Function to insert a node at the end of
# a Circular linked list
def Insert(head, data):
current = head
# Create a new node
newNode = Node(0)
# check node is created or not
if (newNode == None):
print("\nMemory Error\n")
return None
# insert data into newly created node
newNode.data = data
# check list is empty
# if not have any node then
# make first node it
if (head == None) :
newNode.next = newNode
head = newNode
return head
# if list have already some node
else:
# move first node to last node
while (current.next != head):
current = current.next
# put first or head node address
# in new node link
newNode.next = head
# put new node address into last
# node link(next)
current.next = newNode
return head
# Function print data of list
def Display(head):
current = head
# if list is empty, simply show message
if (head == None):
print("\nDisplay List is empty\n")
return
# traverse first to last node
else:
while(True):
print( current.data,end=" ")
current = current.next
if (current == head):
break;
# Function return number of nodes present in list
def Length(head):
current = head
count = 0
# if list is empty
# simply return length zero
if (head == None):
return 0
# traverse first to last node
else:
while(True):
current = current.next
count = count + 1
if (current == head):
break;
return count
# Function delete First node of
# Circular Linked List
def DeleteFirst(head):
previous = head
next = head
# check list have any node
# if not then return
if (head == None) :
print("\nList is empty")
return None
# check list have single node
# if yes then delete it and return
if (previous.next == previous) :
head = None
return None
# traverse second to first
while (previous.next != head):
previous = previous.next
next = previous.next
# now previous is last node and
# next is first node of list
# first node(next) link address
# put in last node(previous) link
previous.next = next.next
# make second node as head node
head = previous.next
return head
# Function to delete last node of
# Circular Linked List
def DeleteLast(head):
current = head
temp = head
previous = None
# check if list doesn't have any node
# if not then return
if (head == None):
print("\nList is empty")
return None
# check if list have single node
# if yes then delete it and return
if (current.next == current) :
head = None
return None
# move first node to last
# previous
while (current.next != head):
previous = current
current = current.next
previous.next = current.next
head = previous.next
return head
# Function delete node at a given position
# of Circular Linked List
def DeleteAtPosition(head, index):
# Find length of list
len = Length(head)
count = 1
previous = head
next = head
# check list have any node
# if not then return
if (head == None):
print("\nDelete Last List is empty")
return None
# given index is in list or not
if (index >= len or index < 0) :
print("\nIndex is not Found")
return None
# delete first node
if (index == 0) :
head = DeleteFirst(head)
return head
# traverse first to last node
while (len > 0):
# if index found delete that node
if (index == count):
previous.next = next.next
return head
previous = previous.next
next = previous.next
len = len - 1
count = count + 1
return head
# Driver Code
head = None
head = Insert(head, 99)
head = Insert(head, 11)
head = Insert(head, 22)
head = Insert(head, 33)
head = Insert(head, 44)
head = Insert(head, 55)
head = Insert(head, 66)
# Deleting Node at position
print("Initial List: ")
Display(head)
print("\nAfter Deleting node at index 4: ")
head = DeleteAtPosition(head, 4)
Display(head)
# Deleting first Node
print("\n\nInitial List: ")
Display(head)
print("\nAfter Deleting first node: ")
head = DeleteFirst(head)
Display(head)
# Deleting last Node
print("\n\nInitial List: ")
Display(head)
print("\nAfter Deleting last node: ")
head = DeleteLast(head)
Display(head)
# This code is contributed by Arnab Kundu
// C# program to delete node at different
// positions from a circular linked list
using System;
class GFG
{
// structure for a node
class Node
{
public int data;
public Node next;
};
// Function to insert a node at the end of
// a Circular linked list
static Node Insert(Node head, int data)
{
Node current = head;
// Create a new node
Node newNode = new Node();
// check node is created or not
if (newNode == null)
{
Console.Write("\nMemory Error\n");
return null;
}
// insert data into newly created node
newNode.data = data;
// check list is empty
// if not have any node then
// make first node it
if (head == null)
{
newNode.next = newNode;
head = newNode;
return head;
}
// if list have already some node
else
{
// move first node to last node
while (current.next != head)
{
current = current.next;
}
// put first or head node address
// in new node link
newNode.next = head;
// put new node address into last
// node link(next)
current.next = newNode;
}
return head;
}
// Function print data of list
static void Display( Node head)
{
Node current = head;
// if list is empty, simply show message
if (head == null)
{
Console.Write("\nDisplay List is empty\n");
return;
}
// traverse first to last node
else
{
do
{
Console.Write("{0} ", current.data);
current = current.next;
} while (current != head);
}
}
// Function return number of nodes present in list
static int Length(Node head)
{
Node current = head;
int count = 0;
// if list is empty
// simply return length zero
if (head == null)
{
return 0;
}
// traverse first to last node
else
{
do
{
current = current.next;
count++;
} while (current != head);
}
return count;
}
// Function delete First node of
// Circular Linked List
static Node DeleteFirst(Node head)
{
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null)
{
Console.Write("\nList is empty\n");
return null;
}
// check list have single node
// if yes then delete it and return
if (previous.next == previous)
{
head = null;
return null;
}
// traverse second to first
while (previous.next != head)
{
previous = previous.next;
next = previous.next;
}
// now previous is last node and
// next is first node of list
// first node(next) link address
// put in last node(previous) link
previous.next = next.next;
// make second node as head node
head = previous.next;
return head;
}
// Function to delete last node of
// Circular Linked List
static Node DeleteLast(Node head)
{
Node current = head, temp = head, previous = null;
// check if list doesn't have any node
// if not then return
if (head == null)
{
Console.Write("\nList is empty\n");
return null;
}
// check if list have single node
// if yes then delete it and return
if (current.next == current)
{
head = null;
return null;
}
// move first node to last
// previous
while (current.next != head)
{
previous = current;
current = current.next;
}
previous.next = current.next;
head = previous.next;
return head;
}
// Function delete node at a given position
// of Circular Linked List
static Node DeleteAtPosition( Node head, int index)
{
// Find length of list
int len = Length(head);
int count = 1;
Node previous = head, next = head;
// check list have any node
// if not then return
if (head == null)
{
Console.Write("\nDelete Last List is empty\n");
return null;
}
// given index is in list or not
if (index >= len || index < 0)
{
Console.Write("\nIndex is not Found\n");
return null;
}
// delete first node
if (index == 0)
{
head = DeleteFirst(head);
return head;
}
// traverse first to last node
while (len > 0)
{
// if index found delete that node
if (index == count)
{
previous.next = next.next;
return head;
}
previous = previous.next;
next = previous.next;
len--;
count++;
}
return head;
}
// Driver Code
public static void Main(String []args)
{
Node head = null;
head = Insert(head, 99);
head = Insert(head, 11);
head = Insert(head, 22);
head = Insert(head, 33);
head = Insert(head, 44);
head = Insert(head, 55);
head = Insert(head, 66);
// Deleting Node at position
Console.Write("Initial List: ");
Display(head);
Console.Write("\nAfter Deleting node at index 4: ");
head = DeleteAtPosition(head, 4);
Display(head);
// Deleting first Node
Console.Write("\n\nInitial List: ");
Display(head);
Console.Write("\nAfter Deleting first node: ");
head = DeleteFirst(head);
Display(head);
// Deleting last Node
Console.Write("\n\nInitial List: ");
Display(head);
Console.Write("\nAfter Deleting last node: ");
head = DeleteLast(head);
Display(head);
}
}
// This code is contributed by Rajput-Ji
<script>
// JavaScript program to delete node at different
// positions from a circular linked list
// A linked list node
class Node{
constructor(new_data){
this.data = new_data
this.next = null
this.prev = null
}
}
// Function to insert a node at the end of
// a Circular linked list
function Insert(head, data){
let current = head
// Create a new node
let newNode = new Node(0)
// check node is created or not
if (newNode == null){
document.write("</br>","Memory Error","</br>")
return null
}
// insert data into newly created node
newNode.data = data
// check list is empty
// if not have any node then
// make first node it
if (head == null){
newNode.next = newNode
head = newNode
return head
}
// if list have already some node
else{
// move first node to last node
while (current.next != head)
current = current.next
// put first or head node address
// in new node link
newNode.next = head
// put new node address into last
// node link(next)
current.next = newNode
}
return head
}
// Function document.write data of list
function Display(head){
let current = head
// if list is empty, simply show message
if (head == null){
document.write("</br>","Display List is empty","</br>")
return
}
// traverse first to last node
else{
while(true){
document.write( current.data," ")
current = current.next
if (current == head)
break;
}
}
}
// Function return number of nodes present in list
function Length(head){
let current = head
let count = 0
// if list is empty
// simply return length zero
if (head == null)
return 0
// traverse first to last node
else{
while(true){
current = current.next
count = count + 1
if (current == head)
break;
}
}
return count
}
// Function delete First node of
// Circular Linked List
function DeleteFirst(head){
let previous = head
let next = head
// check list have any node
// if not then return
if (head == null){
document.write("</br>","List is empty")
return null
}
// check list have single node
// if yes then delete it and return
if (previous.next == previous){
head = null
return null
}
// traverse second to first
while (previous.next != head){
previous = previous.next
next = previous.next
}
// now previous is last node and
// next is first node of list
// first node(next) link address
// put in last node(previous) link
previous.next = next.next
// make second node as head node
head = previous.next
return head
}
// Function to delete last node of
// Circular Linked List
function DeleteLast(head){
let current = head
let temp = head
let previous = null
// check if list doesn't have any node
// if not then return
if (head == null){
document.write("</br>","List is empty")
return null
}
// check if list have single node
// if yes then delete it and return
if (current.next == current){
head = null
return null
}
// move first node to last
// previous
while (current.next != head){
previous = current
current = current.next
}
previous.next = current.next
head = previous.next
return head
}
// Function delete node at a given position
// of Circular Linked List
function DeleteAtPosition(head, index){
// Find length of list
len = Length(head)
count = 1
previous = head
next = head
// check list have any node
// if not then return
if (head == null){
document.write("</br>","Delete Last List is empty")
return null
}
// given index is in list or not
if (index >= len || index < 0) {
document.write("</br>","Index is not Found")
return null
}
// delete first node
if (index == 0){
head = DeleteFirst(head)
return head
}
// traverse first to last node
while (len > 0){
// if index found delete that node
if (index == count){
previous.next = next.next
return head
}
previous = previous.next
next = previous.next
len = len - 1
count = count + 1
}
return head
}
// Driver Code
let head = null
head = Insert(head, 99)
head = Insert(head, 11)
head = Insert(head, 22)
head = Insert(head, 33)
head = Insert(head, 44)
head = Insert(head, 55)
head = Insert(head, 66)
// Deleting Node at position
document.write("Initial List: ")
Display(head)
document.write("</br>","After Deleting node at index 4: ")
head = DeleteAtPosition(head, 4)
Display(head)
// Deleting first Node
document.write("</br>","</br>","Initial List: ")
Display(head)
document.write("</br>","After Deleting first node: ")
head = DeleteFirst(head)
Display(head)
// Deleting last Node
document.write("</br>","</br>","Initial List: ")
Display(head)
document.write("</br>","After Deleting last node: ")
head = DeleteLast(head)
Display(head)
// This code is contributed by shinjanpatra
</script>
OutputInitial List: 99 11 22 33 44 55 66
After Deleting node at index 4: 99 11 22 33 55 66
Initial List: 99 11 22 33 55 66
After Deleting first node: 11 22 33 55 66
Initial List: 11 22 33 55 66
After Deleting last node: 11 22 33 55
Time Complexity: O(N) where N is the number of nodes in given linked list.
Auxiliary Space: O(1)
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