[TODO] FDS (KR) Ass 6 - Set Ops Using Linked Lists

#include <iostream>
#include <string>
using namespace std;

struct Node {
public:
    int roll;
    Node *next;

    Node () {
        next = nullptr;
    }

    Node (int roll) {
        this->roll = roll;
        next = nullptr;
    }
};

class Set {
    Node *hU, *hV, *hB;
    int *UniSet, *Vanilla, *Butterscotch;
    int nU, nV, nB;
    int *r1, *r2, *r3;
    int n1, n2, n3;
    int *arr;
public:
    Set () {
        hU = hV = hB = nullptr;
        UniSet = Vanilla = Butterscotch = nullptr;
    }

    int *fillSet(int cardinality) {
        arr = new int[cardinality];
        for (int i = 0; i < cardinality; i++) {
            cout << "Enter Roll No.: ";
            cin >> arr[i];
        }
        return arr;
    }

    void genU() {
        cout << "\nUniversal Set" << endl;
        cout << "Enter the total number of Students: "; cin >> nU;
        //UniSet = new int[nU];
        UniSet = fillSet(nU);
        hU = createLL(UniSet, nU);
    }

    void genVanilla() {
        cout << "\nVanilla Set" << endl;
        cout << "Enter the number of Students who like Vanilla: "; cin >> nV;
        //Vanilla = new int[nV];
        Vanilla = fillSet(nV);
        hV = createLL(Vanilla, nV);
    }

    void genButterscotch() {
        cout << "\nButterscotch Set" << endl;
        cout << "Enter the number of Students who like Butterscotch: "; cin >> nB;
        //Butterscotch = new int[nB];
        Butterscotch = fillSet(nB);
        hB = createLL(Butterscotch, nB);
    }

    Node *createLL(int *set, int size) {
        if (size == 0) return nullptr;

        Node *head = new Node(set[0]);
        Node *temp = head;

        for (int i = 1; i < size; i++) {
            temp->next = new Node(set[i]);
            temp = current->next;
        }
        return head;
    }

    void display() {
        int choice;
        Node *head = nullptr;
        cout << "1. Universal Set\n2. Vanilla\n3. Butterscotch\n";
        cout << "Enter choice: ";
        if (choice == 1) head = hU;
        else if (choice == 2) head = hV;
        else if (choice == 3) head = hB;
        else cout << "Invalid Choice" << endl;

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

        // No longer needed cuz LL
        // for (int i = 0; i < num; i++) cout << arr[i] << " ";
    }

    // Students who like both vanilla and butterscottch
    void op1() {

        Node *tempV = hV;
        Node *intersectHead = nullptr;
        Node *intersectTail = nullptr;

        while (tempV != nullptr) {
            Node *tempB = hB;
            (while tempB != nullptr) {
                if (tempV->roll == tempB->roll) {
                    Node *newNode = new Node(tempV->roll);
                    if(intersectHead == nullptr) intersectHead = intersectTail = newNode;
                    else {
                        intersectTail->next = newNode;
                        intersectTail = newNode;
                    }

                    break;
                }

                tempB = tempB->next;
            }

            tempA = tempA->next;
        }
    }

    // Stundets who like vanilla or butterscotch or not both
    void op2() {

    }

    // Number of students who like neither  vanilla nor butterscotch
    void op3() {

    }

};