In this problem what does **Two substrings of S are considered different if their positions in S are different** mean ??

**ps**: sorry for dumb title.

In this problem what does **Two substrings of S are considered different if their positions in S are different** mean ??

**ps**: sorry for dumb title.

I think it means something like this:

Consider string “abab”, the substring “ab” and “ab” are considered different as the first “ab” corresponds to index [1,2] while the second corresponds to [3,4]. I am not sure though

yeah but how the index can be same ?