func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);     int tc;     cin >> tc;     while (tc--) {       int n;       cin >> n >> ws;       string str;       cin >> str;       int flag = 0, i;       for (i = 0; i < str.size() - 1; i++) {         if (str[i] > str[i + 1]) {           flag = 1;           break;         }       }       if (flag == 0) {         cout << str << endl;         continue;       }       string clean_str;       for (i = 0; i < str.size(); i++) {         if (str[i] ==  1 ) break;         clean_str.push_back( 0 );       }       clean_str.push_back( 0 );       for (i = str.size() - 1; i >= 0; i--) {         if (str[i] ==  0 ) break;         clean_str.push_back( 1 );       }       cout << clean_str << endl;     }     return 0;   }   