The biggest headache (and performance drain) in the program as it is currently written is the regular expression, which is required because you have no other way of breaking down a Roman numeral.

• 现在写的这个程序中最令人头痛（颇有绞尽脑汁之感性能负担）的是正则表达式，由于没有其他方法来处理罗马数字使得它成了必须它是必需的，因为没有其它方法来处理罗马数字。