func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 100005;   const int MOD = 998244353;   int n;   char s[N];   int solve() {     scanf( %d , &n);     scanf( %s , s);     bool ok = true;     for (int i = 0; i < n;) {       int j = i;       while (j < n && s[j] == s[i]) ++j;       if (s[i] ==  0  && i == 0) {         for (int k = i; k < j; ++k) printf( 0 );       } else if (s[i] ==  1  && j == n) {         for (int k = i; k < j; ++k) printf( 1 );       } else if (s[i] ==  1  && ok) {         printf( 0 );         ok = false;       }       i = j;     }     printf(  n );     return 0;   }   int main() {     int t = 1;     scanf( %d , &t);     while (t--) solve();     return 0;   }   