下班之后，实在不想太动脑筋想问题，直接正则表达式分割字符串，借助哈希解决此题
3167. 字符串的更好压缩

# @param {String} compressed
# @return {String}
def better_compression(compressed)
  compress1 = compressed.split(/[0-9]/)
  compress2 = compressed.split(/[a-z]/)
  compress1.select! {|it| it != ""}
  compress2.select! {|it| it != ""}
  h = {}
  compress1.each_with_index do |c,i|
    unless h.has_key?(c)
      h[c] = compress2[i].to_i
    else
      h[c] += compress2[i].to_i
    end
  end
  h.keys.sort.map {|it| it + h[it].to_s}.join
end