Ds

#include <stdio.h>
#include <stdlib.h>

struct node
{
    int data;
    struct node *next;
};

struct node* insertEnd(struct node *head, int data)
{
    struct node *newnode, *temp;

    newnode = (struct node *)malloc(sizeof(struct node));
    newnode->data = data;
    newnode->next = NULL;

    if(head == NULL)
        return newnode;

    temp = head;

    while(temp->next != NULL)
        temp = temp->next;

    temp->next = newnode;

    return head;
}

struct node* reverse(struct node *head)
{
    struct node *prev = NULL;
    struct node *current = head;
    struct node *next;

    while(current != NULL)
    {
        next = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }

    return prev;
}

struct node* merge(struct node *head1, struct node *head2)
{
    struct node *temp;

    if(head1 == NULL)
        return head2;

    temp = head1;

    while(temp->next != NULL)
        temp = temp->next;

    temp->next = head2;

    return head1;
}

void removeDuplicates(struct node *head)
{
    struct node *current, *temp, *duplicate;

    current = head;

    while(current != NULL)
    {
        temp = current;

        while(temp->next != NULL)
        {
            if(temp->next->data == current->data)
            {
                duplicate = temp->next;
                temp->next = temp->next->next;
                free(duplicate);
            }
            else
            {
                temp = temp->next;
            }
        }

        current = current->next;
    }
}

void display(struct node *head)
{
    while(head != NULL)
    {
        printf("%d -> ", head->data);
        head = head->next;
    }

    printf("NULL\n");
}

int main()
{
    struct node *head1 = NULL;
    struct node *head2 = NULL;

    head1 = insertEnd(head1, 10);
    head1 = insertEnd(head1, 20);
    head1 = insertEnd(head1, 20);
    head1 = insertEnd(head1, 30);

    head2 = insertEnd(head2, 40);
    head2 = insertEnd(head2, 50);

    printf("Original List:\n");
    display(head1);

    head1 = reverse(head1);
    printf("Reversed List:\n");
    display(head1);

    removeDuplicates(head1);
    printf("After Removing Duplicates:\n");
    display(head1);

    head1 = merge(head1, head2);
    printf("After Merging:\n");
    display(head1);

    return 0;
}