OP solved it, closing

Good for you. Here in JS we have to write them ourselves.

Thanks for the sample test. This one helped me work it out. Greatly appreciated :)

I belive that you are confused for "West" with "Left".
Taking 4 Lefts will return you to same point but walking towards west 4 times won't bring you back to point where you started.

It's recommended to fill in the exmaple tests but are not mandatory, and since only a few tests is already mostly sufficient to test for correctness it's not that much of an issue.

The author gave us the maximum size to be expected, so I see no point in worrying about it.

Constraints: 2 ≤ sequence.length ≤ 1000

What's the problem?(I don't understand array with length 100_000+) ;-)

?<= denotes a 'positive lookbehind'.

Basically the regex is looking for any character between a-z(or A-Z, which is unnecessary because the scan() function is automatically case insensitive) where the preceding character is #{letter}

E.g if letter = f

The regex would match fa but not f.

Case insensitive.
So, regex will trigger to AEIOU too.

1 <= n <= 1e9

Do you think your code can create an array of 1000000000 elements and operate multiple times?
What you need is to derive a formula to solve the problem, rather than brute force ;-)

anybody can see it on the dashboard when you post the comment if you didn't hidden it ;-)

two times saw your solution in your comment. Please mark it as having spoiler content next time.

you should to know: is infinite is true, not infinite is false