Submission #723847

#	Time	Username	Problem	Language	Result	Execution time	Memory
723847		OttincaM	Hacker (BOI15_hac)	C++17	0 / 100	0 ms	212 KiB

hac

#include <iostream>
#include <vector>
#include "stdio.h"
#pragma GCC optimize("Ofast,O3,unroll-loops")

using namespace std;
#define int long long
signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    #ifdef WTF
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
        freopen("error.txt", "w", stderr);
    #endif
 
    int n; cin >> n;
    vector <int> a(n + 1);
    for(int i = 1; i <= n; i ++){
        cin >> a[i];
    }

    vector <int> pr(n + 1, 0), sf(n + 2, 0);
    for(int i = 1; i <= n; i ++){
        pr[i] = pr[i - 1] + a[i];
    }  
    for(int i = n; i >= 1; i --){
        sf[i] = sf[i + 1] + a[i];
    }

    int ans = 0;
    for(int i = 1; i <= n; i ++){
        int rg = 0, lf = 0;
        int cnt = n / 2;
        if(i + cnt <= n) rg = pr[i + cnt] - pr[i];
        else {
            rg = pr[n] - pr[i];
            rg += pr[cnt - (n - i)];
        }
        if(i - cnt >= 1) lf = sf[i - cnt] - sf[i];
        else{
            lf = sf[1] - sf[i];
            lf += sf[n - (cnt - (i - 1)) + 1];
        }
        ans = max(ans, pr[n] - max(lf, rg));
    }
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 40