func_code_string: #include <bits/stdc++.h>   using namespace std;   double low = 0, high = 0, mid = 0;   int binary_sear(const vector<int>& v, int x) {     while (1) {       mid = floor((low + high) / 2);       if (low > high) break;       if (v[mid] == x) {         return mid;         break;       } else if (v[mid] < x) {         low = mid + 1;       } else {         high = mid - 1;       }     }     return -1;   }   int binary(vector<int> v, int x) {     mid = floor((low + high) / 2);     cout << low <<     << mid <<     << high << endl;     if (low > high) return -1;     if (v[mid] == x)       return mid;     else if (v[mid] < x) {       low = mid + 1;       return binary(v, x);     } else {       high = mid - 1;       return binary(v, x);     }   }   string decToBinary(int n) {     string s = {};     int i = 0;     while (n > 0) {       s += (n % 2) + 48;       n = n / 2;       i++;     }     reverse(s.begin(), s.end());     return s;   }   int main() {     long long int a, b = 0, c = 1, n, m, mx = 0, mn = 0;     vector<int> v;     bool flag = true, flag2 = true;     cin >> n;     while (n--) {       cin >> m;       for (int i = 0; i < m; i++) {         cin >> a;         if (i == 0) {           b = a;           c = a;           continue;         }         b += a;         c ^= a;       }       cout << 2 << endl;       cout << c <<     << c + b << endl;       b = 0;       c = 1;     }     return 0;   }   