Breaking News: Grepper is joining You.com. Read the official announcement!

program to check if doubly // linked list is palindrome or not in C

Ricardo Echeverria answered on September 23, 2022 Popularity 8/10 Helpfulness 3/10

answer program to check if doubly // linked list is palindrome or not in C

related check if a singly linked list is palindrome or not in c

program to check if doubly // linked list is palindrome or not in C

Comment

// Include header file
#include <stdio.h>
#include <stdlib.h>

// C program for
// Check if palindrome exists in doubly linked list

// This is Linked List Node
typedef struct LinkNode
{
	// Define useful field of LinkNode
	int data;
	struct LinkNode * next;
	struct LinkNode * prev;
}LinkNode;

LinkNode * getLinkNode(int data)
{
	// Create dynamic memory of LinkNode
	LinkNode * ref = (LinkNode * ) malloc(sizeof(LinkNode));
	if (ref == NULL)
	{
		// Failed to create memory 
		return NULL;
	}
	ref->data = data;
	ref->next = NULL;
	ref->prev = NULL;
	return ref;
}
typedef struct DoublyLinkedList
{
	// Define useful field of DoublyLinkedList
	struct LinkNode * head;
	struct LinkNode * tail;
}DoublyLinkedList;

DoublyLinkedList * getDoublyLinkedList()
{
	// Create dynamic memory of DoublyLinkedList
	DoublyLinkedList * ref = 
      (DoublyLinkedList * ) malloc(sizeof(DoublyLinkedList));
	if (ref == NULL)
	{
		// Failed to create memory 
		return NULL;
	}
	// Set head and tail
	ref->head = NULL;
	ref->tail = NULL;
	return ref;
}
// Insert new node at end position
void insert(DoublyLinkedList * ref, int value)
{
	// Create a node
	LinkNode * node = getLinkNode(value);
	if (ref->head == NULL)
	{
		// Add first node
		ref->head = node;
		ref->tail = node;
		return;
	}
	// Add node at last position
	ref->tail->next = node;
	node->prev = ref->tail;
	ref->tail = node;
}
// Display node element of doubly linked list
void display(DoublyLinkedList * ref)
{
	if (ref->head == NULL)
	{
		printf("Empty Linked List");
	}
	else
	{
		printf("Linked List Head to Tail :");
		// Get first node of linked list
		LinkNode * temp = ref->head;
		// iterate linked list 
		while (temp != NULL)
		{
			// Display node value
			printf(" %d ", temp->data);
			// Visit to next node
			temp = temp->next;
		}
		printf("\nLinked List Tail to Head :");
		// Get last node of linked list
		temp = ref->tail;
		// iterate linked list 
		while (temp != NULL)
		{
			// Display node value
			printf(" %d ", temp->data);
			// Visit to prev node
			temp = temp->prev;
		}
	}
}
int isPalindrome(DoublyLinkedList * ref)
{
	if (ref->head == NULL)
	{
		// When empty linked list
		return 0;
	}
	LinkNode * first = ref->head;
	LinkNode * last = ref->tail;
	while (last != NULL && first != NULL && first != last)
	{
		if (first->data != last->data)
		{
			// When node value are not same
			return 0;
		}
		if (first->next == last)
		{
			// When get last pair
			if (first->data == last->data)
			{
				// When pair value is same
				return 1;
			}
			// When last middle node not same
			return 0;
		}
		// Visit to next node
		first = first->next;
		// Visit to previous node
		last = last->prev;
	}
	return 1;
}
int main()
{
	DoublyLinkedList * dll = getDoublyLinkedList();
	// Insert following linked list nodes
	insert(dll, 1);
	insert(dll, 2);
	insert(dll, 4);
	insert(dll, 3);
	insert(dll, 4);
	insert(dll, 2);
	insert(dll, 1);
	// Display all node
	display(dll);
	// Test A
	if (isPalindrome(dll) == 1)
	{
		printf("\nYes\n");
	}
	else
	{
		printf("\nNo\n");
	}
	// Add new element
	insert(dll, 1);
	display(dll);
	// Test B
	if (isPalindrome(dll) == 1)
	{
		printf("\nYes\n");
	}
	else
	{
		printf("\nNo\n");
	}
}

Popularity 8/10 Helpfulness 3/10 Language whatever

Source: kalkicode.com

Tags: c linked-list palindrome whatever

Link to this answer
Share Copy Link

Contributed on Sep 23 2022

Ricardo Echeverria

0 Answers Avg Quality 2/10

Closely Related Answers

check if a singly linked list is palindrome or not in c

Comment

The idea is to use a stack and push all the nodes into the stack,
then again iterate over the linked list to validate
if the linked list is palindrome or not.
by comparing stack-pop against each iteration of linked list
data elements.

Popularity 6/10 Helpfulness 1/10 Language whatever

Source: Grepper

Tags: linked-list c palindrome whatever what

Link to this answer
Share Copy Link

Contributed on Dec 07 2022

Nice Narwhal

0 Answers Avg Quality 2/10

program to check if doubly // linked list is palindrome or not in C

Contents

More Related Answers

program to check if doubly // linked list is palindrome or not in C

Closely Related Answers

check if a singly linked list is palindrome or not in c

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.