// C program to find union
// and intersection of two unsorted
// linked lists
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
/* Linked list node */
struct Node {
int data;
struct Node* next;
};
/* A utility function to insert a
node at the beginning of a linked list*/
void push(struct Node** head_ref, int new_data);
/* A utility function to check if
given data is present in a list */
bool isPresent(struct Node* head, int data);
/* Function to get union of two
linked lists head1 and head2 */
struct Node* getUnion(struct Node* head1,
struct Node* head2)
{
struct Node* result = NULL;
struct Node *t1 = head1, *t2 = head2;
// Insert all elements of
// list1 to the result list
while (t1 != NULL) {
push(&result, t1->data);
t1 = t1->next;
}
// Insert those elements of list2
// which are not present in result list
while (t2 != NULL) {
if (!isPresent(result, t2->data))
push(&result, t2->data);
t2 = t2->next;
}
return result;
}
/* Function to get intersection of
two linked lists head1 and head2 */
struct Node* getIntersection(struct Node* head1,
struct Node* head2)
{
struct Node* result = NULL;
struct Node* t1 = head1;
// Traverse list1 and search each element of it in
// list2. If the element is present in list 2, then
// insert the element to result
while (t1 != NULL) {
if (isPresent(head2, t1->data))
push(&result, t1->data);
t1 = t1->next;
}
return result;
}
/* A utility function to insert a
node at the beginning of a linked list*/
void push(struct Node** head_ref, int new_data)
{
/* allocate node */
struct Node* new_node
= (struct Node*)malloc(sizeof(struct Node));
/* put in the data */
new_node->data = new_data;
/* link the old list of the new node */
new_node->next = (*head_ref);
/* move the head to point to the new node */
(*head_ref) = new_node;
}
/* A utility function to print a linked list*/
void printList(struct Node* node)
{
while (node != NULL) {
printf("%d ", node->data);
node = node->next;
}
}
/* A utility function that returns true if data is
present in linked list else return false */
bool isPresent(struct Node* head, int data)
{
struct Node* t = head;
while (t != NULL) {
if (t->data == data)
return 1;
t = t->next;
}
return 0;
}
/* Driver program to test above function*/
int main()
{
/* Start with the empty list */
struct Node* head1 = NULL;
struct Node* head2 = NULL;
struct Node* intersecn = NULL;
struct Node* unin = NULL;
/*create a linked lists 10->15->5->20 */
push(&head1, 20);
push(&head1, 4);
push(&head1, 15);
push(&head1, 10);
/*create a linked lists 8->4->2->10 */
push(&head2, 10);
push(&head2, 2);
push(&head2, 4);
push(&head2, 8);
intersecn = getIntersection(head1, head2);
unin = getUnion(head1, head2);
printf("\n First list is \n");
printList(head1);
printf("\n Second list is \n");
printList(head2);
printf("\n Intersection list is \n");
printList(intersecn);
printf("\n Union list is \n");
printList(unin);
return 0;
}
