Duplicate entries indexer

Hi,

I am trying a formula which finds the duplicate values in one column and indexes it in another column.

What I am trying to do here is tagging a bunch of one duplicate value to lets say 'A', then another bunch of duplicate values should be tagged to 'B' and so on....Is there a way in doing this?

I got the below code in a similar thread in this forum. I tried with some Char data and it worked

=IF(COUNTIF(B$1:B2,B2)>1,VLOOKUP(B2,B$1:C2,2,FALSE),MAX(C$1:C1)+1)


I am trying this with urls, its not working, it assigns value to the first unique url and doesn;t do the same for duplicates one. I am attaching the url file for reference.

In the file I have:
Column A: URL's
Column B: extracted url from A using formula, basically everything that comes after '?' in the url in Column A has been removed and I get the url I wanted.
Column C: Not important
Column D: above formula applied and should display the desired result.

Can someone please tweak this formula to suit URL's

Thanks,
Joseph

What are the answers supposed to be? All you put in is the non-working formula? Why not put in your desired results instead so we have a clear idea of your goal?