Submission #467490

#	Time	Username	Problem	Language	Result	Execution time	Memory
467490		maeola	Hacker (BOI15_hac)	C++17	100 / 100	463 ms	43844 KiB

hac

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int N;
int A[500069];
vector<int> W[500069];

int main() {
    ios::sync_with_stdio(0);
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }
    int k = (N + 1) / 2;
    int b = k;
    int sum = 0;
    for (int i = 0; i < b; i++) sum += A[i];
    for (int a = 0; a < N; a++) {
        W[a].push_back(sum);
        W[b].push_back(-sum);
        sum = sum + A[b] - A[a];
        b = (b + 1) % N;
    }
    multiset<int> E;
    for (int i = N - k; i < N; i++) {
        for (int a : W[i]) if(a > 0)
            E.insert(a);
    }
    int mx = 0;
    for (int i = 0; i < N; i++) {
        for (int a : W[i]) if(a > 0)
            E.insert(a);

        for (int a : W[i]) if(a < 0)
            E.erase(E.find(-a));

        mx = max(mx, *E.begin());
    }
    cout << mx << '\n';
    return 0;
}

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