#include<bits/stdc++.h> #define MASK(i) (1 << (i)) #define pub push_back #define all(v) v.begin(), v.end() #define compact(v) v.erase(unique(all(v)), end(v)) #define pii pair<int,int> #define fi first #define se second #define endl "\n" #define sz(v) (int)(v).size() #define dbg(x) "[" #x " = " << (x) << "]" #define vi vector<int> using namespace std; bool START_ALLOC; template<class T> bool minimize(T& a, T b){if(a > b) return a = b, true;return false;} template<class T> bool maximize(T& a, T b){if(a < b) return a = b, true;return false;} typedef long long ll; typedef long double ld; mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); ll rand(ll l, ll r){return uniform_int_distribution<ll>(l, r)(rng);} const int MAX = 1e6 + 15; int n, k; int a[MAX]; ll pref[MAX]; ll calc(int l, int r){ if(r > n) r -= n; if(l < 1) l += n; if(l <= r) return pref[r] - pref[l-1]; return pref[n] - (pref[l-1] - pref[r]); } ll f(int i){ ll fh = calc(i, i + k - 1); ll sh = calc(i - k + 1, i); return min(fh, sh); } ll spt[MAX][21]; ll query(int l, int r){ int k = log2(r - l + 1); return min(spt[l][k], spt[r - (1 << k) + 1][k]); } void solve(){ cin >> n; for(int i = 1; i <= n; i++){ cin >> a[i]; pref[i] = pref[i-1] + a[i]; } for(int i = n+1; i <= 2*n; i++){ a[i] = a[i-n]; pref[i] = pref[i-1] + a[i]; } int k = (n + 1) / 2; for(int i = k; i <= 2*n; i++){ spt[i][0] = pref[i] - pref[i - k]; } for(int j = 1; j < 21; j++){ for(int i = k; i + (1 << j) - 1 <= 2*n; i++){ spt[i][j] = min(spt[i][j-1], spt[i + (1 << (j-1))][j-1]); } } ll answer = 0; for(int i = k; i <= 2*n; i++){ maximize(answer, query(i - k + 1, i)); } cout << answer << endl; } bool END_ALLOC; signed main(){ ios_base::sync_with_stdio(NULL); cin.tie(0); cout.tie(0); #define task "task" cerr << "[Static Memory : " << fixed << setprecision(2) << (((&END_ALLOC) - (&START_ALLOC)) / (1024.0 * 1024.0)) << "mb]\n"; if(fopen(task".INP", "r")){ freopen(task".INP", "r", stdin); freopen(task".OUT", "w", stdout); } int t; t = 1; //cin >> t; while(t--) solve(); }

hac.cpp: In function 'int main()':
hac.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~