Re: puzzle with string permutations [photo]

[Emanuel Berg]

> to do it without counting I think the formula is
>
>   n!/(n - r)!
>
> where n is the size of the set - here 26, as
>
>   (length (alphabet t)) ; 26
>
> and r is the number of items to be picked and arranged, or
> here the length of the word.

It doesn't work exactly like that with strings, since for
example the scrambled word "ogod" is actually, here, treated
as

  o_1 g o_2 d

Yet the words

  g o_1 o_2 d 
  g o_2 o_1 d

are duplicates.

So the n, the set or alphabet is A = { d g o }

Yet it's stipulated that o, and only o, must be used twice!

Maybe there is a formula for that as well! Divide by 2 for all
chars that appear twice? But then how to generalize so it
scales for chars that appear thrice and so on?

The truth is out there ...

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