func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<string> v;   int n, m;   void addOne(string &res) {     int i = (int)res.size() - 1;     while (res[i] ==  1 ) {       res[i--] =  0 ;     }     res[i] =  1 ;   }   string toBinary(long long k) {     if (k == 0) {       return string(m,  0 );     }     string res;     while (k) {       res.push_back((k % 2) +  0 );       k >>= 1;     }     while (res.size() != m) {       res.push_back( 0 );     }     reverse(res.begin(), res.end());     return res;   }   void findRes(string &res, long long k) {     long long x = max(k - 100, 0ll);     res = toBinary(x);     int a = lower_bound(v.begin(), v.end(), res) - v.begin();     long long rem = min(100ll, k) + a + (a != n && v[a] == res);     while (rem) {       addOne(res);       rem -= !binary_search(v.begin(), v.end(), res);     }   }   int main() {     int t;     cin >> t;     while (t--) {       cin >> n >> m;       v.resize(n);       for (auto &x : v) {         cin >> x;       }       sort(v.begin(), v.end());       string res(m,  0 );       findRes(res, ((1ll << m) - n - 1) / 2);       cout << res << endl;     }     cin.ignore(2);     return 0;   }   