func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   string s;   bool es[100001];   string ans;   void wk() {     int i;     cin >> n;     cin >> s;     for (i = 0; i <= n; i++) es[i] = false;     int fstone = n;     for (i = 0; i < n; i++)       if (s[i] ==  1 ) {         fstone = i;         break;       }     bool zero = false;     for (i = n - 1; i >= 0; i--) {       if (s[i] ==  0  && zero && fstone < i) es[i] = true;       if (s[i] ==  1  && zero) es[i] = true;       if (s[i] ==  0 ) zero = true;     }     ans =   ;     for (i = 0; i < n; i++)       if (!es[i]) ans += s[i];     cout << ans << endl;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int t;     int i;     cin >> t;     for (i = 1; i <= t; i++) wk();     return 0;   }   