Scala translation

Since the answers can be very large, return only the last 8 digits of the answer in case it exceeds 8 digits. The answers to the test cases will all be shorter than 8 digits.

These two sentences are directly contradictory and one of them needs to be removed, as well as the tests being adjusted to match.

In general there's a lot of room to increase the size of the test inputs such that the modulus requirement is enforced, so I think we should do that.

My code actually passes all tests except two. I understand the expected result for only one these two. Maybe someone could point me into the right direction of how to get to the result of 2533968 if the 'needle' is happy birthday and the 'haystack' is hhhappyyyy biirrrrrthddaaaayyyyyyy to youuuu hhapppyyyy biirtttthdaaay too youuu happy birrrthdayy to youuu happpyyyy birrtthdaaay tooooo youu. Thank you in advance!