p1.rb

#! /usr/bin/ruby
def test(e,f)
    (0..e.length-2).all?{|i| (e[i]-e[i+1]).abs==f[i]}
end
k= ARGV[0].to_i
a= (1..2*k-1).to_a

a.permutation(k).each do |e|
    (a-e).permutation(k-1).each do |f| 
        puts e.to_s, f.to_s if test(e,f.to_a)
    end
end