#include "bits/stdc++.h" #include <bit> using ll = long long; using namespace std; const int N = 1'000'007; const int LEVELS = 20; int max_strips[LEVELS][N]; int getMaxStrip(int l,int r){ int level = bit_width((unsigned)(r-l+1))-1; int size = 1<<level; int k = r-size+1; return max(max_strips[level][k],max_strips[level][l]); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vector<int> a(n); ll total = 0; vector<int> strip_sums; for (int i = 0; i<n; i++){ cin >>a[i]; total+=a[i]; } int k = n/2; int curr = 0; for (int i = 0; i < k; i++){ curr+=a[i]; } int l = 0, r = k-1; for (int i = 0; i < n; i++){ strip_sums.push_back(curr); r = (r+1)%n; curr+=a[r]; curr-=a[l]; l = (l+1)%n; } for (int i = 0; i < n; i++){ max_strips[0][i] = strip_sums[i]; } for (int i = 1; i < LEVELS; i++){ for (int j = 0; j+(1<<i) <= n; j++){ max_strips[i][j] = max(max_strips[i-1][j], max_strips[i-1][j+(1<<(i-1))]); } } int smallest = INT_MAX; for (int i = 0; i < n; i++){ int l = (i+1)%n; int r = (i+ceil((double)n/2)); r%=n; if (l > r){ smallest = min(smallest,max(getMaxStrip(0,r),getMaxStrip(l, n-1))); } else{ smallest = min(smallest,getMaxStrip(l,r)); } } cout << total-smallest; }