func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class A>   void read(vector<A>& v) {     for (auto& x : v) cin >> x;   }   template <class c>   struct rge {     c b, e;   };   template <class c>   rge<c> range(c i, c j) {     return rge<c>{i, j};   }   template <class c>   auto dud(c* x) -> decltype(cout << *x, 0);   template <class c>   char dud(...);   struct debug {     ~debug() { cout << endl; }     template <class c>     typename enable_if<sizeof dud<c>(0) != 1, debug&>::type operator<<(c i) {       cout << boolalpha << i;       return *this;     }     template <class c>     typename enable_if<sizeof dud<c>(0) == 1, debug&>::type operator<<(c i) {       return *this << range(begin(i), end(i));     }     template <class c, class b>     debug& operator<<(pair<b, c> d) {       return *this <<  (  << d.first <<  ,   << d.second <<  ) ;     }     template <class c>     debug& operator<<(rge<c> d) {       *this <<  [ ;       for (auto it = d.b; it != d.e; ++it) *this <<  ,   + 2 * (it == d.b) << *it;       return *this <<  ] ;     }   };   const long MOD = 1000000007;   int main() {     ios::sync_with_stdio(false);     cin.tie(nullptr);     cout.tie(nullptr);     ;     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       int o = 0, z = 0;       for (int _ = 0; _ < n; _++) {         int v;         cin >> v;         if (v == 1)           o++;         else           z++;       }       int times, val;       if (o > z) {         times = o;         val = 1;       } else {         times = z;         val = 0;       }       if (val == 1 && times % 2 && val == 1) times--;       cout << times << endl;       for (int _ = 0; _ < times; _++) cout << val <<    ;       cout << endl;     }   }   