1922A - Tricky Template - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int t;
    cin >> t;
    while (t--)
    {
        int n;
        cin >> n;
        string s1, s2, s3;
        cin >> s1 >> s2 >> s3;
        int f = 0;

        for (int i = 0; i < n; i++)
        {
            if ((s3[i] == s2[i] || s3[i] == s1[i]))
            {
                f = f + 1;
            }
        }

        if (f == n)
        {
            cout << "NO" << endl;
        }
        else
            cout << "YES" << endl;
    }
}