Wow!! Absoulately clever!!

that doesn't change the time complexity: you're comparing things like 3*1 and 1*3.

1. because I already solved it in another language
2. because comments under solutions are visible from the dashboard of any user
3. considering the simplicity of the task, giving away such method name is clearly on a spoiler level.

When you don't know, ask for information, rather than downvote people who are explaining to you that you're making a mistake.

Pretty clever solution :)
Although I want to highlight you end up traversing the main string thrice.

This is beautiful, best code I saw today :)

This solution is very elegant, I'm not not sure how much more expensive is this solution compared to just iterating twice over the input string. Also amount of additional space complexity involved with the new strings that are created. Does any one have an idea?

Ideally it should be something like this:
int remainingPages = itemCount() % itemsPerPage;

if(remainingPages == 0 || pageIndex < pageCount() - 1) return itemsPerPage;
else return remainingPages;

I noticed too, this solution will fail for scenarios when itemsPerPage completely divides totalPages

Check this out: https://en.m.wikipedia.org/wiki/Computational_complexity_of_mathematical_operations#Matrix_algebra

It's possible to do with lower complexity, but I don't know whether the listed method is considered elegant.

Not sure whether to mark this as spoiler or not...

Is there a elegant solution with better complexity? I see most solutions have complexity O(N^3) including mine.

This is neat using a single loop, but has a slighly higher time complexity involved with using replace function.

I agree this is a cool solution but far from following best practices. Runtime complexity for this solution is O(N^2) which can easily be solved in O(N)