Just because your solution doesn't work in all test cases. Try to figure out what is going wrong.

I don't think so. Your solution seems perfect to me. Have you got any problem in passing tests?

Why?

Simple. Round and floor functions aren't the same. For example, round(1.7) = 2, but floor(1.7) = 1.

Since the empty string has no characters, the definition of the problem is ok.

The percentage is a positive number, so the population is always increasing.

Your code is returning 3, but it should return 4 instead.

I am trying to solve this kata in C, but for me it is not clear what I must allocate: words? words_array? or both? Can anyone help me with this?

Thanks for the hint. I was allocating with malloc. I switched to calloc and the bug was fixed.

I think there is a problem with the random tests. I'm coding in C. Take a look at what I got.

n = 9
Submitted: dokuz
Expected: �adokuz

Any idea about what is going on here?

Thanks.

What "2" are you talking about?

That's a good idea tip. Thanks a lot!

Could someone explain what does it mean the error "You must not mutate the input list"? I am a beginner in Python and, although my code inverts correctly the input list, my solution doesn't pass the random tests, probably because of this error that I have no idea how to solve.

You're absolutely right. Now, I've got it. Thanks.