Whats the problem with set approach

#1

#include
#include<unordered_set>
#define ll long long int
using namespace std;
bool subsetzero(ll a[],ll n){
unordered_set s;
ll pre=0;

for(int i=0;i<n;i++){
	pre+=a[i];
	if(pre==0 or s.find(pre)!=s.end()){
		return true;
	}s.insert(pre);
}return false;

}
int main() {
ll t;
cin>>t;
while(t–>0){
ll n;
cin>>n;
ll a[n+1];
for(int i=0;i<n;i++) cin>>a[i];
subsetzero(a,n);
if(subsetzero(a,n)==true) cout<<“No”<<endl;
else cout<<“Yes”<<endl;
}
return 0;
}