func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     pair<long long int, long long int> a[100005];     for (int i = 0; i < n; i++) {       cin >> a[i].first;       a[i].second = i + 1;     }     sort(a, a + n);     if (n % 2 == 0) {       cout << n / 2 << endl;     } else {       cout << n / 2 + 1 << endl;     }     for (int i = 0; i < n; i += 2) {       cout << a[i].second <<    ;     }     cout << endl << n / 2 << endl;     for (int i = 1; i < n; i += 2) {       cout << a[i].second <<    ;     }   }   