Yes i have posted the question first on stackoverflow and they suggested me perlmonks would help you.

Could you provide a link? At the link I posted above there is no such reference to PerlMonks.

Can you please help me?

Well, first of all, it seems the code you posted doesn't work, as opposed to what was posted on StackExchange, so I'll look at the latter.

$ cat input.txt 
5 5
6 11 16 7 12 
$ perl -e '@j=split$",<>;print$% map$%+=2*$q[$_%@j[1]]++,split$",<>' i
+nput.txt 
$ perl -e '@j=split$",<>;map$r+=2*$a[$_%@j[1]]++,split$",<>;print$r' i
+nput.txt 
8
[download]

I take it you're not allowed any switches like e.g. -F? Anyway, here's one idea:

$ perl -e '<>=~/\d+$/;map$r+=2*$a[$_%$&]++,split$",<>;print$r' input.t
+xt
8
[download]

Update: That's 50 chars... what do I win? ;-) Update 2: tybalt89 shows how it's done, very nice :-)