Submission #158668

#	Time	Username	Problem	Language	Result	Execution time	Memory
158668		alishahali1382	Hacker (BOI15_hac)	C++14	100 / 100	79 ms	7756 KiB

hac

#include <bits/stdc++.h>
#pragma GCC optimize ("Ofast")

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;

const ld eps=1e-7;
const int inf=1000000010;
const ll INF=10000000000000010LL;
const int mod = 1000000007;
const int MAXN = 500010, LOG=20;

int n, m, k, u, v, x, y, t, a, b, ans, sum;
int A[MAXN*2];
deque<int> dq;

int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>n;
	m=(n+1)/2;
	for (int i=1; i<=n; i++){
		cin>>A[i];
		A[n+i]=A[i];
	}
	for (int i=1; i<=2*n; i++) A[i]+=A[i-1];
	for (int i=1; i<=n; i++) A[i]=A[i+m]-A[i];
	for (int i=1; i<=n; i++) A[i+n]=A[i];
	//for (int i=1; i<=2*n; i++) cerr<<A[i]<<' ';cerr<<endl;
	for (int i=1; i<=2*n; i++){
		while (dq.size() && A[dq.front()]>A[i]) dq.pop_front();
		dq.push_front(i);
		if (dq.back()<=i-m) dq.pop_back();
		if (i>=m) ans=max(ans, A[dq.back()]);
	}
	cout<<ans<<'\n';
	
	return 0;
}

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