哈尔滨工业大学(威海)第九届ACM程序设计竞赛-G-Virtual Youtuber
地址:https://ac.nowcoder.com/acm/contest/624/G
思路:求前缀和,在从头开始遍历左下标l,二分查找最大<p的下标r,ans+=r-l+1
Code:
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long LL;
const int MAX_N=1e5+5;
int n,T;
LL p;
LL a[MAX_N];
int main()
{
ios::sync_with_stdio(false);
cin>>T;
for(int t=1;t<=T;++t)
{
cin>>n>>p;
for(int i=1;i<=n;++i)
{
cin>>a[i];
a[i]+=a[i-1];
}
LL ans=0;
int k;
for(int i=1;i<=n;++i)
{
k=lower_bound(a+i,a+n+1,a[i-1]+p)-a;
if(k==n+1||a[k]>=a[i-1]+p) --k;
ans+=k-i+1;
}
cout<<"Case #"<<t<<": "<<ans<<endl;
}
return 0;
}