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From: Kaz Kylheku <kaz@kylheku.com>
Newsgroups: comp.lang.ruby
Subject: Re: Short 8 queens solution
Date: Tue, 29 Dec 2015 00:03:19 +0000 (UTC)
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Xref: csiph.com comp.lang.ruby:7181

On 2015-12-28, WJ <w_a_x_man@yahoo.com> wrote:
> (0..7).to_a.permutation{|b|
>   p b if [:+,:-].all?{|op| 8==b.each_with_index.map(&op).uniq.size}}

TXR Lisp:

1> (keep-if
     (op all [list + -] (opip (mapcar @1 (range 0) @@1)
                              uniq
                              length
                              (eql 8)))
     (perm (range 0 7)))
((0 4 7 5 2 6 1 3) (0 5 7 2 6 3 1 4) (0 6 3 5 7 1 4 2) (0 6 4 7 1 3 5 2)
 (1 3 5 7 2 0 6 4) (1 4 6 0 2 7 5 3) (1 4 6 3 0 7 5 2) (1 5 0 6 3 7 2 4)
 (1 5 7 2 0 3 6 4) (1 6 2 5 7 4 0 3) (1 6 4 7 0 3 5 2) (1 7 5 0 2 4 6 3)
 (2 0 6 4 7 1 3 5) (2 4 1 7 0 6 3 5) (2 4 1 7 5 3 6 0) (2 4 6 0 3 1 7 5)
 (2 4 7 3 0 6 1 5) (2 5 1 4 7 0 6 3) (2 5 1 6 0 3 7 4) (2 5 1 6 4 0 7 3)
 (2 5 3 0 7 4 6 1) (2 5 3 1 7 4 6 0) (2 5 7 0 3 6 4 1) (2 5 7 0 4 6 1 3)
 (2 5 7 1 3 0 6 4) (2 6 1 7 4 0 3 5) (2 6 1 7 5 3 0 4) (2 7 3 6 0 5 1 4)
 (3 0 4 7 1 6 2 5) (3 0 4 7 5 2 6 1) (3 1 4 7 5 0 2 6) (3 1 6 2 5 7 0 4)
 (3 1 6 2 5 7 4 0) (3 1 6 4 0 7 5 2) (3 1 7 4 6 0 2 5) (3 1 7 5 0 2 4 6)
 (3 5 0 4 1 7 2 6) (3 5 7 1 6 0 2 4) (3 5 7 2 0 6 4 1) (3 6 0 7 4 1 5 2)
 (3 6 2 7 1 4 0 5) (3 6 4 1 5 0 2 7) (3 6 4 2 0 5 7 1) (3 7 0 2 5 1 6 4)
 (3 7 0 4 6 1 5 2) (3 7 4 2 0 6 1 5) (4 0 3 5 7 1 6 2) (4 0 7 3 1 6 2 5)
 (4 0 7 5 2 6 1 3) (4 1 3 5 7 2 0 6) (4 1 3 6 2 7 5 0) (4 1 5 0 6 3 7 2)
 (4 1 7 0 3 6 2 5) (4 2 0 5 7 1 3 6) (4 2 0 6 1 7 5 3) (4 2 7 3 6 0 5 1)
 (4 6 0 2 7 5 3 1) (4 6 0 3 1 7 5 2) (4 6 1 3 7 0 2 5) (4 6 1 5 2 0 3 7)
 (4 6 1 5 2 0 7 3) (4 6 3 0 2 7 5 1) (4 7 3 0 2 5 1 6) (4 7 3 0 6 1 5 2)
 (5 0 4 1 7 2 6 3) (5 1 6 0 2 4 7 3) (5 1 6 0 3 7 4 2) (5 2 0 6 4 7 1 3)
 (5 2 0 7 3 1 6 4) (5 2 0 7 4 1 3 6) (5 2 4 6 0 3 1 7) (5 2 4 7 0 3 1 6)
 (5 2 6 1 3 7 0 4) (5 2 6 1 7 4 0 3) (5 2 6 3 0 7 1 4) (5 3 0 4 7 1 6 2)
 (5 3 1 7 4 6 0 2) (5 3 6 0 2 4 1 7) (5 3 6 0 7 1 4 2) (5 7 1 3 0 6 4 2)
 (6 0 2 7 5 3 1 4) (6 1 3 0 7 4 2 5) (6 1 5 2 0 3 7 4) (6 2 0 5 7 4 1 3)
 (6 2 7 1 4 0 5 3) (6 3 1 4 7 0 2 5) (6 3 1 7 5 0 2 4) (6 4 2 0 5 7 1 3)
 (7 1 3 0 6 4 2 5) (7 1 4 2 0 6 3 5) (7 2 0 5 1 4 6 3) (7 3 0 2 5 1 6 4))