func_code_string: #include <bits/stdc++.h>   using namespace std;   long long a[200005];   set<long long> ns;   long long p2[100];   int main() {     int n, i, j;     int cnt = 0;     long long t = 1;     while (t < 2000000000) {       cnt++;       p2[cnt] = t;       t *= 2;     }     cin >> n;     for (i = 1; i <= n; i++) {       scanf( %lld , &a[i]);       ns.insert(a[i]);     }     sort(a + 1, a + 1 + n);     for (i = 2; i < n; i++) {       for (j = 1; j <= cnt; j++) {         long long t1 = a[i] - p2[j], t2 = a[i] + p2[j];         if (ns.find(t1) != ns.end() && ns.find(t2) != ns.end()) {           puts( 3 );           cout << t1 <<     << a[i] <<     << t2 << endl;           return 0;         }       }     }     for (i = 2; i <= n; i++) {       for (j = 1; j <= cnt; j++) {         long long t1 = a[i] - p2[j];         if (ns.find(t1) != ns.end()) {           puts( 2 );           cout << t1 <<     << a[i] << endl;           return 0;         }       }     }     puts( 1 );     cout << a[1] << endl;     return 0;   }   