CodeIQ 結城浩さん出題「スペーストーキー問題」（不完全）

spacetalky.rb

def enc_string(s)
  repeated = Hash[("a".."z").to_a.zip (1..26)]
  n = s.length
  decoded = []
  i = 0
  while i < n
    chars = s[i..i+1]
    decoded << chars[0] * repeated[chars[1]]
    i += 2
  end
  decoded.join()
end

out_file = File.open("out.txt", "w")

File.open("words.txt", "r") do |file|
  file.each do |line|
    line.chomp!
    if line.length%2 == 0
      out_file.print enc_string(line), ":#{line}\n"
    else
      out_file.print "X:#{line}\n"
    end
  end
end

out_file.close