[end.is.forever]

Prova così:

public int [] calcola(int [] input)
{
   int [] output = new int[input.length];
   for (int i = 0; i < input.length; i++)
   {      
       output[i] = 0;
       for(int s = 0; s < input.length; s++)
       {
            if (s < i)
                output[i] += input[s];
            else
                if (s > i)
                     output[i] -= input[s];
       }
    }
    return output;
}

Ciao