shindan.rb

require "digest/md5"

d = Digest::MD5.hexdigest("nyan" + Time.now.strftime("%Y%m%d")).to_i(16);

shindan = []

10.times {|n| shindan[n] = []; 99.times {|nn| shindan[n] << nn.to_s } }

result = []

shindan.each_with_index {|item, i|
  srand(d + i)
  result << item[rand(item.length)]
}

p result.join('-')