Submission #479436

#	Time	Username	Problem	Language	Result	Execution time	Memory
479436		Lobo	Hacker (BOI15_hac)	C++17	60 / 100	82 ms	14224 KiB

hac

#include <bits/stdc++.h>
 
using namespace std;

const long long INFll = (long long) 1e18 + 10;
const int INFii = (int) 1e9 + 10;
typedef long long ll;
typedef int ii;
typedef long double dbl;
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

#define maxn 1050000

ii n, v[maxn], r[maxn], ps[maxn]; 

int main() {
    ios::sync_with_stdio(false); cin.tie(0);

    //freopen("in.in", "r", stdin);
    //freopen("out.out", "w", stdout);

    cin >> n;

    for(ii i = 1; i <= n; i++) {
        cin >> v[i];
        v[i+n] = v[i];
    }

    for(ii i = 1; i <= 2*n; i++) {
        ps[i] = ps[i-1] + v[i];
        r[i] = INFii;
    }

    ii ans = 0;
    ii sz = (n+1)/2;
    //cout << sz << endl;

    if(n > 6e3) {
        ii i = 1;
        for(ii j = 0; j < sz; j++) {
            if(i+j <= 2*n && i-sz+j >= 0) {
                //cout << " " << j << "  " << i-sz+j+1 << " " << i+j << " " << ps[i+j] - ps[i-sz+j] << endl;
                r[i] = min(r[i],ps[i+j] - ps[i-sz+j]);
            }
        }
        i = n+1;
        for(ii j = 0; j < sz; j++) {
            if(i+j <= 2*n && i-sz+j >= 0) {
                //cout << " " << j << "  " << i-sz+j+1 << " " << i+j << " " << ps[i+j] - ps[i-sz+j] << endl;
                r[i] = min(r[i],ps[i+j] - ps[i-sz+j]);
            }
        }

        cout << min(r[1],r[n+1]) << endl;
        return 0;
    }

    for(ii i = 1; i <= 2*n; i++) {
        //cout << i << endl;
        for(ii j = 0; j < sz; j++) {
            if(i+j <= 2*n && i-sz+j >= 0) {
                //cout << " " << j << "  " << i-sz+j+1 << " " << i+j << " " << ps[i+j] - ps[i-sz+j] << endl;
                r[i] = min(r[i],ps[i+j] - ps[i-sz+j]);
            }
        }
    }

    for(ii i = 1; i <= n; i++) {
        ans = max(ans, min(r[i],r[i+n]));
        //cout << i << " " << min(r[i],r[i+n]) << endl;
    }

    cout << ans << endl;



}

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