Submission #1205939

#	Time	Username	Problem	Language	Result	Execution time	Memory
1205939		CrabCNH	Hacker (BOI15_hac)	C++20	100 / 100	260 ms	180676 KiB

hac

#include <bits/stdc++.h>

#define task     "BriantheCrab"

#define int    long long
#define pii    pair <int, int>
#define fi     first
#define se     second
#define szf    sizeof
#define sz(s)  (int)((s).size())
#define all(v) (v).begin(), (v).end()

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using namespace std;

template <class T> void minimize (T &t, T f) {if (t > f) t = f;}
template <class T> void maximize (T &t, T f) {if (t < f) t = f;}

const int maxN = 1e6 + 5;
const int maxlg = 20;
const int inf = 1e18 + 7;
const int mod = 1e9 + 7;

int a[maxN], pfs[maxN], lg[maxN];
int st[maxN][maxlg];

int get (int l, int r) {
    int k = lg[r - l + 1];
    return min (st[l][k], st[r - (1 << k) + 1][k]);
}

void solve () {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i ++) {
        cin >> a[i];
        a[n + i] = a[i];
    }
    for (int i = 1; i <= n * 2; i ++) {
        pfs[i] = pfs[i - 1] + a[i];
    }
    for (int i = 2; i < maxN; i ++) {
        lg[i] = lg[i >> 1] + 1;
    }
    for (int i = 1; i <= n * 2; i ++) {
        st[i][0] = pfs[i + (n + 1) / 2 - 1] - pfs[i - 1];
    }
    for (int l = 1; l <= lg[n * 2]; l ++) {
        for (int i = 1; i + (1 << l) - 1 <= n * 2; i ++) {
            st[i][l] = min (st[i][l - 1], st[i + (1 << (l - 1))][l - 1]);
        }
    }
    int res = 0;
    for (int i = (n + 1) / 2; i <= n * 2; i ++) {
        maximize (res, get (i - (n + 1) / 2 + 1, i));
    }
    cout << res;
    return;
}

signed main () {
    cin.tie (nullptr) -> sync_with_stdio (false);
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    int t = 1;
    //cin >> t;
    while (t --) {
        solve ();
    } 
    return 0;
}
// thfv

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:67:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:68:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40