func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 1;   void solve() {     long long int n, x, ans = 1, p = -1, q = -1, c;     cin >> n;     set<long long int> s;     long long int a[n];     for (long long int i = 0; i < n; i++) cin >> a[i], s.insert(a[i]);     for (long long int i = 0; i < n; i++) {       for (long long int j = 0; j < 32; j++) {         c = 1;         if (s.find(a[i] - (1 << j)) != s.end()) {           q = a[i] - (1 << j);           c++;         }         if (s.find(a[i] + (1 << j)) != s.end()) {           q = a[i] + (1 << j);           c++;         }         if (c == 3) {           cout << 3 <<   n ;           cout << a[i] - (1 << j) <<     << a[i] <<     << a[i] + (1 << j);           return;         }         if (c == 2) p = a[i];         ans = max(ans, c);       }     }     cout << ans <<   n ;     if (ans == 2) cout << p <<     << q;     if (ans == 1) cout << a[0];   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int t = 1;     while (t--) {       solve();     }     return 0;   }   