Hey, Bruno. I had run through these topics regarding 191-7. I had found another solution in:
The proposed solution counts the number of distinct tracks in an album and the number of distinct tracks in an invoice, compares both and considers it an album purchase if the numbers are equal, isn’t it?
However, can’t we have some false positives in doing so? I mean, cases when the number of distinct tracks in an invoice are the same number of tracks in an album but the tracks themselves are different? In this situation, the invoice will be called an album purchase but it should not be.
I am not sure if I misinterpreted the code, though.