Journey to the Moon

My Solution to "Journey to the Moon" hackerrank question. All testcases pass.

https://www.hackerrank.com/challenges/journey-to-the-moon

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <vector>
#include <list>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>
#include <numeric>
#include <cstdlib>
#include <cmath>
#include <cstdio>
#include <fstream>
#include <ctime>
#include <cassert>

using namespace std;

int connected (int a, int b, vector<vector<int>> & v) {
    queue<int> q;
    vector<int> v1(v.size(), 0);
    for (int i = 0; i< v[a].size(); i++) {
        q.push(v[a][i]);
    }
    v1[a] = 1;
    while(!q.empty()) {
        if (q.front() == b) return 1;
        if (v1[q.front()] == 0) {
            for (int i = 0; i< v[q.front()].size(); i++) {
                    q.push(v[q.front()][i]);
            }
        }
        v1[q.front()] = 1;
        q.pop();
    }
    return 0;
}

int main()
{
    int N, I;
    int c = 0;
    long long c1 = 0;
    cin >> N >> I;
    vector<vector<int> > pairs(N);
    vector<vector<int> > country;
    vector<int> v(N,0);
    vector<int> v1(N,0);
    for (int i = 0; i < I; ++i) {
        int a, b;
        cin >> a >> b;
        pairs[a].push_back(b);
        pairs[b].push_back(a);
    }

    long long result = 0;
   
    /** Write code to compute the result using N,I,pairs **/
    for (int i = 0; i < N; ++i) {
        if (v[i] == 0 && pairs[i].size() > 0) {
            vector<int> v2(0);
            country.push_back(v2);
            country[c].push_back(i);
            v1[i] = 1;
            for (int j = 0; j<pairs[i].size(); j++) {
                if (v1[pairs[i][j]] == 0)
                    country[c].push_back(pairs[i][j]);
                v1[pairs[i][j]] = 1;
            }
            v[i] = 1;
            for(int k = 0; k<country[c].size(); k++) {
                if (v[country[c][k]] == 0) {
                    for (int j = 0; j<pairs[country[c][k]].size(); j++) {
                        if (v1[pairs[country[c][k]][j]] == 0)
                            country[c].push_back(pairs[country[c][k]][j]);
                        v1[pairs[country[c][k]][j]] = 1;
                    }
                }
                v[country[c][k]] = 1;
            }
            c++;
            //cout<<"here";
        } else {
            if (pairs[i].size() == 0) {
                //vector<int> v2(0);
                //country.push_back(v2);
                //country[c].push_back(i);
                c1++;
            }
        }
       
    }
   
    for (int i = 0; i<country.size(); i++) {
        for (int j = i +1; j<country.size(); j++) {
            result = result + country[i].size() * country[j].size();
        }
    }
    long long temp =0;
    for (int i = 0; c1>0 && i<country.size(); i++)
        temp = temp + country[i].size();
    if (c1> 0) result = result + (c1*(c1-1))/2 + temp*c1;
    cout << result <<endl;
    return 0;
}