From: "David A. Black" <dblack@...>
Date: 2005-11-14T23:43:18+09:00
Subject: Re: Recursive functions

Hi --

On Mon, 14 Nov 2005, hans.sjunnesson@gmail.com wrote:

> I know that this is a trivial problem, but I'm having a hard time
> solving it with tuby. I could use a little extra help with my
> programming in ruby skills.
>
> The problem I'm faced to solving (taken from a puzzle in a newspaper)
> is a series of alphabetical triplets like:
>
> ubc
> deg
> lap
> pyq
>
> ved
> run
> pac
> ken
> alm
> mli
> rnt
> alg
>
> Combining a letter from each triplet, you can form words which will
> form a sentence (in the above case: 'ugly duckling').
> What I want to do is go through all possible permutations of
> characters, in the triplets, and crossreference them with a dictionary
> to create all possible permutations of words in a sentence. I've put
> the above triplets into an array of arrays: [["ubc", "deg", "lap",
> "pyq"], ["ved", "run", "pac", "ken", "alm", "mli", "rnt", "alg"]]. Now
> here's my problem. How do I recurse the words in the best way? What I
> want to do is start to check "udlp", "udly", "udlq", then "udap",
> "uday", "udaq" and so on? I know it's a computer practise to have a
> function call itself. Is that needed here? Because I'm running into a
> problem having nested loops, because the words are of variable length.
> Any ideas on this?

Several years ago I wrote a Boggle program in Ruby (actually networked
Boggle), which did something similar.  I don't remember exactly
what I did, and I'm afraid I don't have time to remind myself and
comment on it, but I can send it to you if you're interested.


David

-- 
David A. Black
dblack@wobblini.net