analysis
After
subtracting the average value of the two-point column , judge whether it is non-negative. If the
two-point value is subtracted, just add a small decimal every time.
Then update the max prefix and the new s[il] to take min each time
Upload code
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
double jq=1e-5;
int n,c,d;
double l,r,a[100001],s[100001];
int pd(double x)
{
double mi=1e10,ans=-1e10;
memset(s,0,sizeof(s));
for(int i=1;i<=n;i++)
{
s[i]=s[i-1]+a[i]-x;
}
for(int i=c;i<=n;i++)
{
mi=min(mi,s[i-c]);
ans=max(ans,s[i]-mi);
}
return ans>=0;
}
int main()
{
cin>>n>>c;
for(int i=1;i<=n;i++)
{
cin>>a[i];
}
l=-1e6;r=1e6;
while(l+jq<r)
{
double mid=(l+r)/2;
if(pd(mid)) l=mid;
else r=mid;
}
d=r*1000;
cout<<d;
return 0;
}