Project 1 - Creation of user defined data type to implement the user interfaces for working with ‘Set’ (Mathematical Set theory) using Linked List

ANSWER.

#include <iostream>
#include <map>
#include <unordered_set>
#include <stdlib.h>
using namespace std;

class LinkedList {
public:
struct Node {
int data;
Node* next;
Node(int d)
: data(d)
, next(nullptr)
{
}
};
Node* head = nullptr;

void printList()
{
Node* temp = head;
while (temp != nullptr) {
cout << temp->data << " ";
temp = temp->next;
}
cout << endl;
}

void push(int new_data)
{
Node* new_node = new Node(new_data);
new_node->next = head;
head = new_node;
}

void append(int new_data)
{
if (head == nullptr) {
Node* n = new Node(new_data);
head = n;
return;
}
Node* n1 = head;
Node* n2 = new Node(new_data);
while (n1->next != nullptr) {
n1 = n1->next;
}
n1->next = n2;
n2->next = nullptr;
}

bool isPresent(Node* head, int data)
{
Node* t = head;
while (t != nullptr) {
if (t->data == data)
return true;
t = t->next;
}
return false;
}

LinkedList getIntersection(Node* head1, Node* head2)
{
unordered_set<int> hset;
Node* n1 = head1;
Node* n2 = head2;
LinkedList result;

while (n1 != nullptr) {
if (hset.find(n1->data) == hset.end()) {
hset.insert(n1->data);
}
n1 = n1->next;
}

while (n2 != nullptr) {
if (hset.find(n2->data) != hset.end()) {
result.push(n2->data);
}
n2 = n2->next;
}
return result;
}

LinkedList getUnion(Node* head1, Node* head2)
{
map<int, int> hmap;
Node* n1 = head1;
Node* n2 = head2;
LinkedList result;

while (n1 != nullptr) {
if (hmap.find(n1->data) != hmap.end()) {
hmap[n1->data]++;
}
else {
hmap[n1->data] = 1;
}
n1 = n1->next;
}

while (n2 != nullptr) {
if (hmap.find(n2->data) != hmap.end()) {
hmap[n2->data]++;
}
else {
hmap[n2->data] = 1;
}
n2 = n2->next;
}

for (auto it = hmap.begin(); it != hmap.end();
it++) {
result.append(it->first);
}
return result;
}
};

int main()
{
LinkedList llist1, llist2, intersection, union_list;

llist1.push(2);
llist1.push(4);
llist1.push(6);
llist1.push(9);

llist2.push(3);
llist2.push(5);
llist2.push(4);
llist2.push(9);

intersection = intersection.getIntersection(
llist1.head, llist2.head);
union_list
= union_list.getUnion(llist1.head, llist2.head);

cout << "First List is" << endl;
llist1.printList();

cout << "Second List is" << endl;
llist2.printList();

cout << "Intersection List is" << endl;
intersection.printList();

cout << "Union List is" << endl;
;
union_list.printList();
}

OUTPUT: