func_code_string: #include <bits/stdc++.h>   using namespace std;   int a[100005], b[100005];   bool compare(int c, int d) { return a[c - 1] < a[d - 1]; }   int main() {     int n;     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a[i];       b[i] = i + 1;     }     sort(b, b + n, compare);     cout << (n + 1) / 2 << endl;     for (int i = 0; i < n; i += 2) cout << b[i] <<    ;     cout << endl << n / 2 << endl;     for (int i = 1; i < n; i += 2) cout << b[i] <<    ;     cout << endl;     return 0;   }   