Submission #1316702

#	Time	Username	Problem	Language	Result	Execution time	Memory
1316702		tkhoi13	Hacker (BOI15_hac)	C++20	100 / 100	38 ms	7168 KiB

hac

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define db double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define pb push_back
#define all(x) begin(x), end(x)
#define allr(x) rbegin(x), rend(x)
#define szx(x) ((int)(x).size())
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; ++i)
#define ROF(i, a, b) for (int i = a, _b = (b); i >= _b; --i)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define endl '\n'
#define inf 1000000007
#define mod 1000000007
// #define mod 998244353

using namespace std;
using namespace __gnu_pbds;

void setIO() {
    ios::sync_with_stdio(0);
    cin.tie(0);
}
void openFile(string filename = "") {
    if (!filename.empty())
        if (ifstream(filename + ".in")) {
            freopen((filename + ".in").c_str(), "r", stdin);
            freopen((filename + ".out").c_str(), "w", stdout);
        }
}

const int MAX = 5e5 + 5;
int n;
int a[MAX], sum[MAX];

int id(int x) { return x >= n ? x - n : x; }

void solve() {
    int window = (n + 1) / 2;
    vector<int> b(n, inf);
    deque<int> q;
    int s = 0;
    FOR(i, 0, n + window) {
        if (i - window + 1 > 0) s -= a[id(i - window)];
        s += a[id(i)];
        if (i - window + 1 >= 0) sum[id(i - window + 1)] = s;
    }

    FOR(i, 0, n + window - 1) {
        if (!q.empty() && q.front() == i - window) q.pop_front();
        while (!q.empty() && sum[id(q.back())] >= sum[id(i)]) q.pop_back();
        q.push_back(i);
        if (i - window + 1 >= 0) b[id(i)] = min(b[id(i)], sum[id(q.front())]);
    }

    cout << *max_element(all(b));
}

void input() {
    cin >> n;
    REP(i, n) cin >> a[i];
}

void preprocess() {}

void reset() {}

int main() {
    setIO();
    openFile("main");
    int t = 1;
    // cin >> t;
    preprocess();
    while (t--) {
        reset();
        input();
        solve();
    }
}

Compilation message (stderr)

hac.cpp: In function 'void openFile(std::string)':
hac.cpp:32:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |             freopen((filename + ".in").c_str(), "r", stdin);
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:33:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |             freopen((filename + ".out").c_str(), "w", stdout);
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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