Submission #633167

#	Time	Username	Problem	Language	Result	Execution time	Memory
633167		Alma	Hacker (BOI15_hac)	C++17	0 / 100	0 ms	212 KiB

hac

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

#define fi first
#define se second
using ll = long long;
using ii = pair<int,int>;

const int INF = 1e9;
const ll LLINF = 1e18;
using vi = vector<int>;
using vvi = vector<vi>;

void setIO (string fileName) {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    if (fileName != "std") {
        freopen((fileName + ".in").c_str(), "r", stdin);
        freopen((fileName + ".out").c_str(), "w", stdout);
    }
}

int main() {
    setIO("std");

    int n;
	cin >> n;
	vector<ll> a(3*n), p(3*n);
	for (int i = 0; i < n; i++) {
		cin >> a[i];
		a[n+i] = a[2*n+i] = a[i];
	}
	p[0] = a[0];
	for (int i = 1; i < 3*n; i++) {
		p[i] = p[i-1] + a[i];
	}
	ll ans = 0, h = (n+1) / 2;
	for (int i = n; i < 2*n; i++) {
		if (a[i-1] == a[i+1]) {
			ans = max(ans, p[i] - p[i-h]);
			ans = max(ans, p[i+h-1] - p[i-1]);
		} else if (a[i-1] > a[i+1]) {
			ans = max(ans, p[i+h-1] - p[i-1]);
		} else {
			ans = max(ans, p[i] - p[i-h]);
		}
	}
	cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

hac.cpp: In function 'void setIO(std::string)':
hac.cpp:18:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |         freopen((fileName + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hac.cpp:19:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |         freopen((fileName + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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