**萌新刚学OI**
by lion0514 @ 2020-10-13 20:57:48
~~qndmx~~
by Fangfx @ 2020-10-13 21:04:53
qndmx
by LuomuQDM @ 2020-10-13 21:06:44
啥错误？
by zzqDeco @ 2020-10-13 22:00:01
@[引领天下](/user/39863) 错误信息
by zzqDeco @ 2020-10-13 22:00:16
@[zzqDeco](/user/62573) WA了
by 引领天下 @ 2020-10-14 00:05:23
@[引领天下](/user/39863) 是不是longlong啥的问题，或者是没取模
by zzqDeco @ 2020-10-14 07:29:54
我放我的代码在这里吧，你自己看看
```cpp
#include <cstdio>
#include <algorithm>
using namespace std;
int n;
long long a[1000010],b[1000010],c[1000010],sum[1000010],f[1000010],mod=1000000009;
void add(int x,long long v)
{
for(;x<=n;x+=x&-x) c[x]=(c[x]+v)%mod;
}
long long query(int x)
{
long long res=0;
for(;x;x-=x&-x) res=(res+c[x])%mod;
return res;
}
int main()
{
scanf("%d",&n);
for(int i=1;i<=n;i++) scanf("%lld",&a[i]);
for(int i=1;i<=n;i++) sum[i]=sum[i-1]+a[i],b[i]=sum[i];
b[n+1]=0;
sort(b+1,b+n+2);
int cnt=unique(b+1,b+n+2)-b-1;
for(int i=1;i<=n;i++) sum[i]=lower_bound(b+1,b+cnt+1,sum[i])-b;
add(lower_bound(b+1,b+cnt+1,0)-b,1);
for(int i=1;i<=n;i++)
{
f[i]=query(sum[i]);
add(sum[i],f[i]);
}
printf("%lld",f[n]);
}
```
by zzqDeco @ 2020-10-14 08:01:13
@[zzqDeco](/user/62573) https://www.luogu.com.cn/record/39808807 CE了
by 引领天下 @ 2020-10-14 20:47:24
@[引领天下](/user/39863) 应该是洛谷原因（这个就不要找我了吧qwq，而且我是完隐
by zzqDeco @ 2020-10-14 20:51:41