# Problem 89: Roman numerals
For a number written in Roman numerals to be considered valid there are
basic rules which must be followed. Even though the rules allow some
numbers to be expressed in more than one way there is always a "best"
way of writing a particular number. For example, it would appear that
there are at least six ways of writing the number sixteen:
IIIIIIIIIIIIIIII VIIIIIIIIIII VVIIIIII XIIIIII VVVI XVI However,
according to the rules only XIIIIII and XVI are valid, and the last
example is considered to be the most efficient, as it uses the least
number of numerals. The 11K text file, roman.txt (right click and 'Save
Link/Target As...'), contains one thousand numbers written in valid, but
not necessarily minimal, Roman numerals; see About... Roman Numerals for
the definitive rules for this problem. Find the number of characters
saved by writing each of these in their minimal form. Note: You can
assume that all the Roman numerals in the file contain no more than four
consecutive identical units.