#include <bits/stdc++.h>
#define lowbit(x) (x&(-x))
#define int long long
#define ll long long
using namespace std;
inline int read(){
	int w = 0 , f = 1;
	char ch = getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while('0'<=ch&&ch<='9'){
		w=w*10+(ch-'0');
		ch=getchar();
	}
	return w*f;
}
const int N = 1e5+15,MOD=1e9+9;
int n,a[N];
ll sum[N],dp[N],b[N];
struct BIT{
	ll tr[N];
	BIT(){
		memset(tr,0,sizeof(tr));
	}
	void change(int x,ll k){
		for(int i = x ; i<=n ; i+=lowbit(i)){
			tr[i]+=k;
			tr[i]%=MOD;
		}
		return ;
	}
	ll query(int x){
		ll sum = 0;
		for(int i = x ; i>0 ; i-=lowbit(i)){
			sum+=tr[i];
			sum%=MOD;
		}
		return sum;
	}
}T;
signed main(){
	n = read();
	for(int i = 1 ; i<=n ; i++){
		a[i]=read();
		sum[i]=sum[i-1]+a[i];
		b[i]=sum[i];
	}
	b[n+1]=0;
	sort(b+1,b+n+2);
	int m = unique(b+1,b+n+2) - b - 1;
	for(int i = 1 ; i<=n+1 ; i++){
		sum[i]=upper_bound(b+1,b+m+1,sum[i]) - b;
	}
	T.change(sum[n+1],1);
	for(int i = 1 ; i<=n ; i++){
		dp[i]=T.query(sum[i]);
		T.change(sum[i],dp[i]);
	}
	cout<<dp[n];
	return 0;
}

By the way : 调试代码有哪些好方法or好功能（比如Dev-C++的动态调试虽然我并不会用，求动态调试教程）