probably the same i'm through.. That's because random tests sometimes are 40 OK and 10 left and sometimes 49 ok and 1 left.. It's all about randomness

I was actually able to submit a solution with an "incorrect" answer.

I coded a correct solution, but then I wanted to make a new one using only one loop. It seemed correct, but when I hit attempt, the "random number" case failed. I wanted to debug it, so I tried again but this time it worked. I accidentally submitted it. After that, I finally debugged it correctly and found out that my solution only failed when the array ended with a 0, so it is now fixed.

To sum it up, I think test cases for arrays starting and/or ending with 0 might be useful.