Submission #31601

#	Time	Username	Problem	Language	Result	Execution time	Memory
31601		huynd2001	Hacker (BOI15_hac)	C++14	100 / 100	106 ms	15844 KiB

hac

/*huypheu
5
1 1 1 1 1
*/

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

int a[500007];
int su[500007];
int ar[500007];

signed main()
{
	int n;
	scanf("%lld",&n);
	for(int i=1;i<=n;i++)
	{
		scanf("%lld",&a[i]);
	}
	int k=(n/2)+(n%2!=0);
	for(int i=1;i<=n;i++)
	{
		su[i]=su[i-1]+a[i];
	}
	for(int i=1;i<=n;i++)
	{
		if(i+k-1<=n) 
		{
			ar[i]=su[i+k-1]-su[i-1];
		}
		else
		{
			ar[i]=su[n]-su[i-1]+su[k-(n-i+1)];
		}
	}
	// for(int i=1;i<=n;i++) cout << ar[i] << endl;
	for(int i=n+1;i<=2*n;i++)
	{
		ar[i]=ar[i-n];
	}
	deque <int> deq;
	int ans=0;
	for(int i=1;i<=2*n;i++)
	{
		while(!deq.empty() && deq.front()<=(i-k)) deq.pop_front();
		while(!deq.empty() && ar[deq.back()]>ar[i]) deq.pop_back();
		deq.push_back(i);
		if(i>=k) ans=max(ans,ar[deq.front()]);
	}
	printf("%lld",ans);
	// int mi=0;
	// for(int i=2;i<=n-la+1;i++)
	// {
	// 	mi=max(mi,su[i+la-1]-su[i-1]);
	// }
	// printf("%lld",su[n]-mi);
	return 0;
}

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:17:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld",&n);
                  ^
hac.cpp:20:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&a[i]);
                      ^

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