From: Robert Dober <robert.dober@...>
Date: 2006-12-18T02:50:58+09:00
Subject: Re: [QUIZ] Chess960 (#106)

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Here is my solution to #106 I thaught I'll make a more readable amb based
soluytion but I did not succeed so far :(, maybe I'll come up with it before
not too long.
-----------------------------------------
#!/usr/bin/ruby
class Chess960
    class ::Range
        class << self
            def free= args
                @@free = args
            end
        end
        def each_free
            each do
                |ele|
                next unless @@free.include? ele
                @@free.delete ele
                yield ele
                @@free.unshift ele
            end
        end #def each_free
    end

    N = 8
    def initialize
        @solutions = []
        Range.free = [*1..N]
        init
        generate
    end
    def [] sol_nb
        @solutions[ sol_nb ]
    end

    private
    def init
        @sol="Q " * N
    end
    def generate
        (1..N-1).each_free do
            |@b1|
            (@b1.succ..N).each_free do
                |@b2|
                next if @b1 & 1 == @b2 & 1
                (1..N-2).each_free do
                    |@r1|
                    (@r1.succ..N-1).each_free do
                        |@k|
                        (@k.succ..N).each_free do
                            |@r2|
                            (1..N-1).each_free do
                                |@n1|
                                (@n1.succ..N).each_free do
                                    |@n2|
                                    save_solution
                                end
                            end
                        end #(@k.succ..N).each_free do
                    end
                end #(1..N-2).each_free do
            end
        end
    end
    def save_solution
        @sol[2*(@b1-1)]= ?B
        @sol[2*(@b2-1)]= ?B
        @sol[2*(@r1-1)]= ?R
        @sol[2*(@r2-1)]= ?R
        @sol[2*(@n1-1)]= ?N
        @sol[2*(@n2-1)]= ?N
        @sol[2*(@k-1)] = ?K

        @solutions << @sol
        init
    end

end

c = Chess960.new
puts %<enter a number to show a specific solution (0 based) or
enter r for a random solution or
enter q to go back to work>
until (n = gets.strip) =~ /^q/i
    i = n.to_i
    i = rand(960) if n =~ /^r/i
    puts "Solution #{i}"
    puts c[i]
end
-----------------------------------------

Cheers
Robert
-- 
"The real romance is out ahead and yet to come. The computer revolution
hasn't started yet. Don't be misled by the enormous flow of money into bad
defacto standards for unsophisticated buyers using poor adaptations of
incomplete ideas."

- Alan Kay

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