Hi y’all, puzzle creator here.
The 007 test case seems to be a struggle for many. If you’re one of them, make sure that your code considers spaces as any other character. Don’t trim the input for example, since the 007 test case has a space among the last typed keys.
I also added an Out of bounds 2 test case to have the expected behaviour better explained when it comes to boundaries.
@nguyen.lam did you make it work in the end?
@Razovsky getline() seems to include the last space, do you still have that issue?
Thanks a lot @5DN1L for helping people until now, I made sure to subscribe to this topic in case of future questions 
Good luck!