From: Eric Promislow <eric.promislow@...>
Date: 2007-08-06T01:40:08+09:00
Subject: Re: Determining the common prefix for several strings

On Aug 3, 3:30 pm, Eric Promislow <eric.promis...@gmail.com> wrote:
> The obligatory solution usingzip...
>
> # data contains a list of strings
> aa = data.map{ |x| x.split(//)}
> bz = aa[0].zip(*(aa[1 .. -1])).map{ |x| x.join("")}
> target = bz.index( bz.find{ |x| x.squeeze.size != 1})
> answer = (target.nil? ? aa[0] :
>           target >= 1 ? aa[0][0 .. target - 1] :
>           []).join("")
>
> - Eric

Doh!  This isn't correct.  It's hard to improve over
Michael's routine back in the initial response.  You
need to find any one of the shortest strings, remove it,
and use that instead of aa[0] as above.