Closest or Equal Pair to a Given x (Two Pointer Technique)

#include<bits/stdc++.h>

using namespace std;

int main()

{

    int n, m, x;

    cout << "Enter First Array Size :: ";

    cin >> n;

    vector<int>a(n);

    cout << "\nEnter First Array Element :: ";

    for(int i=0; i<n; i++)

        cin >> a[i];

    cout << "\nEnter Second Array Size :: ";

    cin >> m;

    vector<int>b(m);

    cout << "\nEnter Second Array Element :: ";

    for (int i=0; i<m; i++)

        cin >> b[i];

    cout << "\nEnter Which Element you want :: ";

    cin >> x;

    sort(a.begin(), a.end());

    sort(b.begin(), b.end());

    int difference = INT_MAX, i = 0, j = m-1, first = -1, second = -1, f = 0;

    while(i<n && j>=0)

    {

        if(abs(a[i] + b[j] - x) < difference)

        {

            f = 1;

            first = i;

            second = j;

            difference = abs(a[i] + b[j] - x);

        }

        if(difference == 0)

        {

            f = 2;

            break;

        }

        if(a[i] + b[j] > x)

            j--;

        else

            i++;

    }

if(f == 1)

cout << "\nClosest Pair are :: " << a[first] << " and " << b[second] << "\n";

else if(f == 2)

cout << "\nEqual Pair are :: " << a[first] << " and " << b[second] << "\n";

else

cout << "\nPair Not Found." << "\n";

    return 0;

}