Submission #1020502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020502		owoovo	Hacker (BOI15_hac)	C++17	100 / 100	43 ms	21808 KiB

hac

#include<bits/stdc++.h>
#define ll long long
#define F first 
#define S second 
using namespace std;
ll ori[1000010],pre[1000010],n,len;
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>ori[i];
        ori[i+n]=ori[i];
    }
    for(int i=1;i<=2*n;i++){
        pre[i]=pre[i-1]+ori[i];
    }
    len=(n+1)/2;
    ll ans=0;
    deque<pair<ll,ll>> dq;
    for(int i=len;i<=2*n;i++){
        while(!dq.empty()&&dq.front().F<=i-len)dq.pop_front();
        ll ne=pre[i]-pre[i-len];
        while(!dq.empty()&&dq.back().S>=ne)dq.pop_back();
        dq.push_back({i,ne});
        if(i>=len*2-1){
            ans=max(ans,dq.front().S);
        }
    }
    cout<<ans<<"\n";
    
    return 0;
}

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