暴力枚举
#include <bits/stdc++.h>
using namespace std;
const int MAXN =
2e4+
10;
int num[MAXN];
int main()
{
int n;
ios::sync_with_stdio(
false);
cin >> n;
for(
int i =
0; i < n; ++i)
cin >> num[i];
int res = -
999999999;
for(
int i =
1; i <= n/
3; ++i)
{
if(n%i)
continue;
for(
int j =
0; j < i; ++j)
{
int sum =
0;
for(
int k = j; k < n; k += i)
sum += num[k];
if(sum > res)
res = sum;
}
}
cout << res << endl;
}