#include #pragma GCC diagnostic ignored "-Wsign-compare" #pragma GCC diagnostic ignored "-Wsign-conversion" #define NDEBUG using i32 = int32_t; using i64 = int64_t; using u32 = uint32_t; using u64 = uint64_t; using uint = unsigned int; using usize = std::size_t; using ll = long long; using ull = unsigned long long; using ld = long double; template constexpr T popcount(const T u) { return u ? static_cast(__builtin_popcountll(static_cast(u))) : static_cast(0); } template constexpr T log2p1(const T u) { return u ? static_cast(64 - __builtin_clzll(static_cast(u))) : static_cast(0); } template constexpr T msbp1(const T u) { return log2p1(u); } template constexpr T lsbp1(const T u) { return __builtin_ffsll(u); } template constexpr T clog(const T u) { return u ? log2p1(u - 1) : static_cast(u); } template constexpr bool ispow2(const T u) { return u and (static_cast(u) & static_cast(u - 1)) == 0; } template constexpr T ceil2(const T u) { return static_cast(1) << clog(u); } template constexpr T floor2(const T u) { return u == 0 ? static_cast(0) : static_cast(1) << (log2p1(u) - 1); } template constexpr bool btest(const T mask, const usize ind) { return ((static_cast(mask) >> ind) & static_cast(1)); } template constexpr T bcut(const T mask, const usize ind) { return ind == 0 ? static_cast(0) : static_cast((static_cast(mask) << (64 - ind)) >> (64 - ind)); } template bool chmin(T& a, const T& b) { return (a > b ? a = b, true : false); } template bool chmax(T& a, const T& b) { return (a < b ? a = b, true : false); } constexpr unsigned int mod = 1000000007; template constexpr T inf_v = std::numeric_limits::max() / 4; template constexpr Real pi_v = Real{3.141592653589793238462643383279502884}; template T read() { T v; return std::cin >> v, v; } template std::vector read_vec(const std::size_t size) { std::vector v(size); for (auto& e : v) { std::cin >> e; } return v; } template auto read_vals() { return std::tuple...>{read()...}; } #define SHOW(...) static_cast(0) template std::vector make_v(const std::size_t size, T v) { return std::vector(size, v); } template auto make_v(const std::size_t size, Args... args) { return std::vector(size, make_v(args...)); } template class wavelet_matrix { public: using bucket_type = u64; static constexpr usize bucket_size = sizeof(bucket_type) * 8; template wavelet_matrix(const InIt first, const InIt last) : sz{static_cast(std::distance(first, last))} { std::vector b(sz); std::vector v{first, last}; for (usize d = 0; d < lg; d++) { std::vector z, o; for (usize i = 0; i < sz; i++) { b[i] = btest(v[i], lg - d - 1), (b[i] ? o : z).push_back(v[i]); } table.push_back(fid{b}), zero.push_back(z.size()); for (usize i = 0; i < z.size(); i++) { v[i] = z[i]; } for (usize i = 0; i < o.size(); i++) { v[z.size() + i] = o[i]; } } } usize less_than(usize l, usize r, const bucket_type v) const { usize ans = 0; for (usize i = 0; i < lg; i++) { if (btest(v, lg - i - 1)) { ans += table[i].zero(r) - table[i].zero(l), l = zero[i] + table[i].one(l), r = zero[i] + table[i].one(r); } else { l = table[i].zero(l), r = table[i].zero(r); } } return ans; } usize range_freq(const usize l, const usize r, const bucket_type vmin, const bucket_type vsup) const { return less_than(l, r, vsup) - less_than(l, r, vmin); } private: class fid { private: const usize sz; std::vector data; std::vector large; public: fid(const std::vector& b) : sz(b.size()), data(sz / bucket_size + 2, 0), large(sz / bucket_size + 2, 0) { for (usize i = 0; i < sz; i++) { data[i / bucket_size] |= (static_cast(b[i]) << (i % bucket_size)), large[i / bucket_size + 1] += b[i]; } for (usize i = 1; i < large.size(); i++) { large[i] += large[i - 1]; } } bool operator[](const usize n) const { return btest(data[n / bucket_size], n % bucket_size); } usize one(const usize n) const { return large[n / bucket_size] + popcount(bcut(data[n / bucket_size], n % bucket_size)); } usize zero(const usize n) const { return n - one(n); } }; const usize sz; std::vector zero; std::vector table; }; template class sparse_table { public: using semigroup_type = SemiGroup; using value_type = typename semigroup_type::value_type; template sparse_table(const InIt first, const InIt last) : lg{clog(static_cast(std::distance(first, last) + 1))}, table(lg, std::vector(1 << lg)) { const usize cap = 1 << lg; for (usize d = 0, base = 1; d < lg; d++, base <<= 1) { std::copy(first, last, table[d].begin()); for (usize b = 0; b < cap / base; b++) { if (b % 2 == 1) { for (usize i = 1; i < base; i++) { table[d][b * base + i] = semigroup_type::merge(table[d][b * base + i - 1], table[d][b * base + i]); } } else { for (usize i = 1; i < base; i++) { table[d][(b + 1) * base - i - 1] = semigroup_type::merge(table[d][(b + 1) * base - i - 1], table[d][(b + 1) * base - i]); } } } } } value_type fold(const usize l, const usize r) const { assert(l < r); if (r - l == 1) { return table[0][l]; } const usize d = log2p1(r ^ l) - 1; return semigroup_type::merge(table[d][l], table[d][r - 1]); } private: const usize lg; std::vector> table; }; template, typename B = uint64_t> class linear_rmq { public: using value_type = Value; using comparator_type = Comp; using bucket_type = B; static constexpr usize bucket_size = sizeof(bucket_type) * 8; template linear_rmq(const InIt first, const InIt last) : sz{static_cast(std::distance(first, last))}, bucket_num{(sz + bucket_size - 1) / bucket_size}, val{first, last}, bucket_val([&]() { std::vector ans(bucket_num); for (usize i = 0; i < sz; i++) { ans[i / bucket_size] = i % bucket_size == 0 ? val[i] : std::min(ans[i / bucket_size], val[i], comparator_type{}); } return ans; }()), masks(sz, 0), stable(bucket_val.begin(), bucket_val.end()) { for (usize i = 0; i < bucket_num; i++) { std::vector g(bucket_size, sz); std::stack stack; for (usize j = 0; j < bucket_size and i * bucket_size + j < sz; j++) { for (; not stack.empty() and not comparator_type{}(val[stack.top()], val[i * bucket_size + j]); stack.pop()) {} g[j] = stack.empty() ? sz : stack.top(), stack.push(i * bucket_size + j); } for (usize j = 0; j < bucket_size and i * bucket_size + j < sz; j++) { masks[i * bucket_size + j] = g[j] == sz ? static_cast(0) : (masks[g[j]] | static_cast(1) << (g[j] - i * bucket_size)); } } } value_type fold(const usize l, const usize r) const { assert(l < r), assert(r <= sz); const usize left_bucket = (l + bucket_size - 1) / bucket_size, right_bucket = r / bucket_size; if (left_bucket > right_bucket) { return internal(l, r); } else { return left_bucket < right_bucket ? (l < bucket_size * left_bucket ? (bucket_size * right_bucket < r ? std::min({stable.fold(left_bucket, right_bucket), internal(l, bucket_size * left_bucket), internal(bucket_size * right_bucket, r)}, comparator_type{}) : std::min(stable.fold(left_bucket, right_bucket), internal(l, bucket_size * left_bucket), comparator_type{})) : (bucket_size * right_bucket < r ? std::min(stable.fold(left_bucket, right_bucket), internal(bucket_size * right_bucket, r), comparator_type{}) : stable.fold(left_bucket, right_bucket))) : (l < bucket_size * left_bucket ? (bucket_size * right_bucket < r ? std::min(internal(l, bucket_size * left_bucket), internal(bucket_size * right_bucket, r), comparator_type{}) : internal(l, bucket_size * left_bucket)) : (bucket_size * right_bucket < r ? internal(bucket_size * right_bucket, r) : value_type{})); } } usize size() const { return sz; } private: value_type internal(const usize l, usize r) const { r--; const B w = masks[r] >> (l % bucket_size); return w == 0 ? val[r] : val[l + lsbp1(w) - 1]; } const usize sz, bucket_num; std::vector val, bucket_val; std::vector masks; struct min { using value_type = Value; static value_type merge(const value_type& a, const value_type& b) { return std::min(a, b, comparator_type{}); } }; sparse_table stable; }; int main() { const auto n = read(); const auto a = read_vec(n); auto b = a; constexpr ll MAX = 1000000000; for (usize i = 0; i < n; i++) { b[i] += MAX; } wavelet_matrix<32> wm(b.begin(), b.end()); linear_rmq rmq(b.begin(), b.end()); linear_rmq> rMq(b.begin(), b.end()); auto median = [&](const usize l, const usize r) -> ll { ll inf = rmq.fold(l, r) - 1, sup = rMq.fold(l, r) + 1; while (sup - inf > 1) { const ll mid = (inf + sup) / 2; const usize low = wm.less_than(l, r, mid); (low * 2 < r - l ? inf : sup) = mid; } return inf - MAX; }; ll ans = 0; for (usize k = 1; k <= n; k++) { std::vector left{0}, right{0}; for (usize l = 0; l + k <= n; l += k) { left.push_back(median(l, l + k) * (ll)k); } for (int r = (int)n; r - (int)k >= 0; r -= k) { right.push_back(median(r - k, r) * (ll)k); } const usize s = left.size() - 1; for (usize i = 1; i <= s; i++) { left[i] += left[i - 1], right[i] += right[i - 1]; } for (usize i = 1; i <= s; i++) { chmax(left[i], left[i - 1]), chmax(right[i], right[i - 1]); } for (usize i = 0; i <= s; i++) { chmax(ans, left[i] + right[s - i]); } } std::cout << ans << std::endl; return 0; }