Why isn't this code getting accepted ? it is giving the correct answer for a variety of cases

// i used kadane which was giving wrong answer for negative values
// hence i generated all the possible subarrays
int main() {
long int t,a[10000];
long int n;
cin>>t;

while(t>0)
{
    cin>>n;
	cin>>a[0];
	for(int i=1 ; i<n ; i++)
	{
		cin>>a[i];
		a[i]+=a[i-1];
		
	}
//sub array

int csum=0,msum=0;

for(int i=0 ; i<n-1 ; i++)
{
	
	for(int j=i+1 ; j<n ; j++)
	{
      csum=a[j]-a[i];
	 
	 if(csum>msum)
	 {
		 msum=csum;
	 }
	}
	

}

if(msum<a[n-1])
{
	msum=a[n-1];
}
    cout<<msum<<endl; 
	t--;
	
}

return 0;

}