Connect cities

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

class city
{
private:
list<city*>* connected;
public:
    bool been = false;
    city(){
        connected = new list<city*>;
    };
    ~city(){};

    void connect(city* other) {
        connected->push_back(other);
        other->connected->push_back(this);
    };

    void visitGroup() {
        list<city*>* group = new list<city*>;
        group->push_back(this);
        for (auto c=group->begin(); c!=group->end(); c++) {
            city* cc = *c;
            if (cc->been) {
                continue;
            }
            else {
                cc->been = true;
                for (auto c2=cc->connected->begin(); c2!=cc->connected->end(); c2++) {
                    if (!(*c2)->been) {
                        group->push_back(*c2);
                    }
                }
            }
        }
    }
};

int main() {
    int n, m;
    cin >> n >> m;
    city* cities = new city[n];

    for (int i=0; i<m; i++) {
        int a, b;
        cin >> a >> b;
        cities[a-1].connect(&cities[b-1]);
    }

    list<int> groups = {};
    for (int i=0; i<n; i++) {
        if (!cities[i].been) {
            groups.push_back(i);
            cities[i].visitGroup();
        }
    }
    cout << groups.size() - 1 << endl;
    for (auto i=++groups.begin(); i!=groups.end(); i++) {
        cout << *groups.begin() + 1 << " " << *i + 1 << "\n";
    }

    delete[] cities;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED