#include #include using namespace std; #define DEBUG(x) cerr<<#x<<": "< #define vl vector #define vii vector< vector > #define vll vector< vector > #define vs vector #define pii pair #define pis pair #define psi pair #define pll pair template pair operator+(const pair &s, const pair &t) { return pair(s.first + t.first, s.second + t.second); } template pair operator-(const pair &s, const pair &t) { return pair(s.first - t.first, s.second - t.second); } template ostream& operator<<(ostream& os, pair p) { os << "(" << p.first << ", " << p.second << ")"; return os; } #define X first #define Y second #define rep(i,n) for(int i=0;i<(n);i++) #define rep1(i,n) for(int i=1;i<=(n);i++) #define rrep(i,n) for(int i=(n)-1;i>=0;i--) #define rrep1(i,n) for(int i=(n);i>0;i--) #define REP(i,a,b) for(int i=a;i bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; } #define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end()); const ll inf = 1000000001; const ll INF = (ll)1e18 + 1; const ll MOD = 1000000007; //const ll MOD = 998244353; const double pi = 3.14159265358979323846; #define Sp(p) cout<> n; vi a(n); rep (i, n) { cin >> a[i]; } ll ans = 0; rep1 (k, n) { int num = n / k; vi b = a, c = a; vl x1, x2; for (int i = 0; i + k <= n; i += k) { nth_element(b.begin() + i, b.begin() + i + (k - 1) / 2, b.begin() + i + k); x1.push_back((ll)b[i + (k - 1) / 2] * k); } for (int i = n - k; i >= 0; i -= k) { nth_element(c.begin() + i, c.begin() + i + (k - 1) / 2, c.begin() + i + k); x2.push_back((ll)c[i + (k - 1) / 2] * k); } assert(x1.size() == x2.size() and x1.size() == num); vl sum1(num + 1), sum2(n + 1); rep (i, num) { sum1[i + 1] = sum1[i] + x1[i]; sum2[i + 1] = sum2[i] + x2[i]; } rep (i, num) { chmax(sum2[i + 1], sum2[i]); } rep (i, num + 1) { chmax(ans, sum1[i] + sum2[num - i]); } } cout << ans << endl; }