I Love strings

#include <iostream>
#include <bits/stdc++.h>
using namespace std ;
typedef long long ll ;

int main() {
    ios_base::sync_with_stdio(false) , cin.tie(nullptr) , cout.tie(nullptr) ;
    int n ;
    cin >> n ;
    string s , t ;
    while (n--) {
        cin >> s >> t ;
        for (int i = 0; i < max(s.size() , t.size()); i++) {
            if (s[i] == '\0') cout << t[i] ;
            else if (t[i] == '\0') cout << s[i] ;
            else cout << s[i] << t[i] ;
        }
        cout << "\n" ;
    }

    return 0 ;
}