Salut!
Ai rezolvarea in C++ mai jos
#include <iostream>
using namespace std;
int main()
{
int n, a[1001], cnt = 0;
cin >> n;
for (int i = 1; i <= n; ++i)
{
cin >> a[i];
}
for (int i = 1; i < n; ++i)
{
for (int j = i + 1; j <= n; ++j)
{
if ((a[i] + a[j]) % n == 0)
{
cnt++;
}
}
}
cout << cnt;
return 0;
}
