#include <bits/stdc++.h> using namespace std; #define TIME (1.0 * clock() / CLOCKS_PER_SEC) #define rf if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);} #define bit(i, mask) (((mask) >> (i)) & 1) #define ll long long #define fi first #define se second #define pii pair<int, int> #define vi vector<int> #define all(a) (a).begin(), (a).end() #define len(x) ((int)(x).size()) #define pb push_back #define endl '\n' #define name "test" template<typename T1, typename T2> bool mini(T1 &a, T2 b) {if(a > b) a = b; else return 0; return 1;} template<typename T1, typename T2> bool maxi(T1 &a, T2 b) {if(a < b) a = b; else return 0; return 1;} const int mod = 1e9 + 7; const int inf = 1e9 + 9; const ll oo = 1e18l + 7; const int M = 5e5 + 6; const int N = 1e6 + 6; const int LOG = 31 - __builtin_clz(N); int n, a[N]; ll pre[N], sum[N], ans[N]; void inp(){ cin >> n; for(int i = 1; i <= n; i++) cin >> a[i]; } void proc(){ for(int i = 1; i <= 2 * n; i++) pre[i] = pre[i - 1] + a[i + (i > n ? -n : 0)]; int len = (n + 1) / 2; for(int i = 1; i <= 2 * n; i++){ if(i <= n) sum[i] = pre[i + len - 1] - pre[i - 1]; else sum[i] = sum[i - n]; } deque<int> dq; for(int i = 1; i <= 2 * n; i++){ while(!dq.empty() && dq.front() < i - len + 1) dq.pop_front(); while(!dq.empty() && sum[dq.back()] >= sum[i]) dq.pop_back(); dq.pb(i); if(i >= len) ans[i - len + 1] = sum[dq.front()]; } ll res = 0; for(int i = 1; i <= n; i++) maxi(res, ans[i]); cout << res; } int main(){ cin.tie(nullptr)->sync_with_stdio(false); rf int test = 1; // cin >> test; while(test--){ inp(); proc(); } cerr << "Time elapsed: " << TIME << "s" << endl; return 0; }

hac.cpp: In function 'int main()':
hac.cpp:6:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    6 | #define rf if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);}
      |                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:63:5: note: in expansion of macro 'rf'
   63 |     rf
      |     ^~
hac.cpp:6:80: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    6 | #define rf if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);}
      |                                                                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:63:5: note: in expansion of macro 'rf'
   63 |     rf
      |     ^~