#!/usr/bin/env ruby

# ===========================================
# palindrom.rb
# -------------------------------------------
# Novejsi verze ;-) Upraveno: 20050217-000500
# Autor: Wejn
# Licence: GPL
# -------------------------------------------
# Ruby = http://www.ruby-lang.org/
# ===========================================

dom = [0, 1, 2] # experimentalne zjisteno, ze pro (3..9) uz zadny neexistuje
szi = 9
szo = 17
results = {}

class Palindrom
    def Palindrom.generate(domain, size, &block)
        raise "No block given" if block.nil?
        gen(domain.map { |x| x.to_s }, size/2, size%2!=0, "", &block)
    end

    def Palindrom.gen(dom, half, odd, res, &p)
        if half > 0
            dom.each do |x|
                gen(dom, half - 1, odd, res + x, &p)
            end
        else
            (odd ? dom : [""]).each do |x|
                p.call(res + x + res.reverse)
            end
        end
    end
end

Palindrom.generate(dom, szi) do |pal|
    mult = ((pal.to_i)**2).to_s
    results[pal] = mult if mult.size == szo && mult == mult.reverse
end

num = 0
results.sort.each do |k,v|
    num += 1
    puts "#{k}: #{v}"
end
puts "Pocet: #{num}"

=begin
Vysledek:

wejn@ns ~ $ ruby ./palindrom.rb 
100000001: 10000000200000001
100010001: 10002000300020001
100020001: 10004000600040001
100101001: 10020210401202001
100111001: 10022212521222001
100121001: 10024214841242001
101000101: 10201020402010201
101010101: 10203040504030201
101020101: 10205060806050201
101101101: 10221432623412201
101111101: 10223454745432201
110000011: 12100002420000121
110010011: 12102202520220121
110020011: 12104402820440121
110101011: 12122232623222121
110111011: 12124434743442121
111000111: 12321024642012321
111010111: 12323244744232321
111101111: 12343456865434321
111111111: 12345678987654321
200000002: 40000000800000004
200010002: 40004000900040004
Pocet: 22
=end

# vim: set et ts=4 :