I had the same thing happen. It turns out that number with the dashes was not the number provided by the test. When I was breaking the long arg into individual digits, I was doing (int) n%10 instead of (int) (n%10), which was not giving the desired digits (with some being negative numbers), causing the stack trace later on.

I have just tried a few solutions and it worked fine. I don't understand why you had that...

OK but is it your printing? The inputs are numbers, not strings. Java?

Yes, it's weird. Basic tests or rando tests?

For input string: "6834172015468-4-3-92-4"

Is it your printing?