#include using namespace std; template void chmax(T& a, const T b){a=max(a,b);} inline void balanceLtoR(multiset& stl,multiset& str) { while(stl.size()>str.size()+1) { long long tmp = *stl.rbegin(); str.insert(tmp); stl.erase(stl.find(tmp)); } } inline void balanceRtoL(multiset& stl,multiset& str) { if(stl.size()& stl,multiset& str){ long long tmpl = *stl.rbegin(); long long tmpr = *str.begin(); if(tmpl>tmpr) { stl.erase(stl.find(tmpl)); stl.insert(tmpr); str.erase(str.find(tmpr)); str.insert(tmpl); } } int main() { cin.tie(0);ios::sync_with_stdio(false); int N; cin >> N; assert(1<=N && N <= 10000); vector A(N); for(int i = 0; i < N; ++i) cin >> A[i]; for(int i = 0; i < N; ++i) assert(-1000000000<=A[i] && A[i] <= 1000000000); //クエリ区間を列挙、調和級数なのでO(N*logN) vector> range; for(int i = 1; i <= N; ++i) { for(int j = 0; j+i <= N; j+=i) range.push_back({j,j+i-1}); for(int j = N; 0 <= j-i; j-=i) range.push_back({j-i,j-1}); } //Mo順ソート O(N*logN*log(NlogN)) int bucket = sqrt(N); vector idx(range.size()); iota(idx.begin(),idx.end(),0); sort(idx.begin(),idx.end(),[&](int a, int b){ auto al = range[a].first/bucket; auto& ar = range[a].second; auto bl = range[b].first/bucket; auto& br = range[b].second; return (al != bl) ? (al < bl) : ((al%2)?(ar > br):(ar < br)); }); //Moで中央値列挙 O(N*sqrt(N)*(logN)^2) int l = 0, r = 0; multiset stl,str; stl.insert(A[0]); unordered_map mp; for(int& i:idx){ auto& xl = range[i].first; auto& xr = range[i].second; //左端を広げる while(xl < l){ l--; stl.insert(A[l]); if(str.size()) exchange(stl,str); balanceLtoR(stl,str); } //右端を広げる while(r < xr){ r++; stl.insert(A[r]); if(str.size()) exchange(stl,str); balanceLtoR(stl,str); } //左端を狭める while(l < xl){ if(stl.count(A[l])) { stl.erase(stl.find(A[l])); balanceRtoL(stl,str); } else { str.erase(str.find(A[l])); balanceLtoR(stl,str); } l++; } //左端を狭める while(xr < r){ if(stl.count(A[r])) { stl.erase(stl.find(A[r])); balanceRtoL(stl,str); } else { str.erase(str.find(A[r])); balanceLtoR(stl,str); } r--; } mp[xl*N+xr] = *stl.rbegin(); } long long ans = 0; int cnt = 0; //区間長決め打ち全探索O(N*logN) for(long long i = 1; i <= N; ++i) { int M = N/i; vector lSum(M,0),rSum(M,0); vector> lRange(M),rRange(M); //区間取得 for(int j = 0; j < M; ++j) lRange[j] = range[cnt+j]; for(int j = M-1; 0 <= j; --j) rRange[j] = range[cnt + 2*M-1 - j]; //中央値取得 for(int j = 0; j < M; ++j) lSum[j] = i*mp[lRange[j].first*N+lRange[j].second]; for(int j = M-1; 0 <= j; --j) rSum[j] = i*mp[rRange[j].first*N+rRange[j].second]; //累積和 for(int j = 1; j < M; ++j) lSum[j] += lSum[j-1]; for(int j = M-2; 0 <= j; --j) rSum[j] += rSum[j+1]; //累積max for(int j = 1; j < M; ++j) chmax(lSum[j],lSum[j-1]); for(int j = M-2; 0 <= j; --j) chmax(rSum[j],rSum[j+1]); chmax(ans,lSum[M-1]); chmax(ans,rSum[0]); //尺取りしながら左右決め打ち全探索 int k = 0; for(int j = 0; j < M; ++j) { while(k < M && range[cnt + j].second >= range[cnt + 2*M-1-k].first) k++; if(k