From: George Ogata <g_ogata@...>
Date: 2002-08-10T18:26:10+09:00
Subject: Re: Coding challenge (on Ruby Garden)

Christoph wrote:

> Your solution fails, i.e. it returns false, for
> 
>     items = [1,2,2]
>     row =   [1,2]
>     rows = [ row, row, [1,3]]

Good point.

Hmm, I wonder if I can get away with it by being pedantic about the wording of the 
requirements.

<quote src="spec">
But this doesn't work:

  array:   [1,2]
  a-of-as: [ [1,2,3,4], [5,6,7,8] ]

because the 1 and the 2 both get placed in the same array; it's
a many-to-one correspondence.
</quote>

In your example, the 1 and the 2 get "placed in the same array".  The array just appears 
more than once.  Or does it have to be a capitalized "Array" for this argument to hold?

Oh well, if it's not acceptable, then:

def one_in_each
i,r;i==[]||r.find{|s|s.member?(i[0])&&one_in_each(i[1..-1],((d=r.dup).slice!r.index
s;d))}!=nil;end

(115 chars --- replace newlines with spaces.)