#92
Read Roman numerals
| Difficulty: | Hard |
| Topics: | strings math |
Roman numerals are easy to recognize,
but not everyone knows all the rules necessary to work with them.
Write a function to parse a Roman-numeral string
and return the number it represents.
You can assume that the input will be well-formed,
in upper-case, and follow the subtractive principle.
You don't need to handle any numbers greater than MMMCMXCIX (3999),
the largest number representable with ordinary letters.
 | (= 14 (__ "XIV")) |
| (= 827 (__ "DCCCXXVII")) |
| (= 3999 (__ "MMMCMXCIX")) |
| (= 48 (__ "XLVIII")) |