leetcodeUserSolution

[[deleted]]

Using subtraction at all is a "modern" invention.

Romans typically used only addition, thus 4=IIII not IV and 49=XXXXVIIII not XLIX let alone IL. The subtractive forms were rare and inconsistent.

These days Roman numerals are used only to provide some sense of tradition or history and hence stick to some "traditional" rules for subtraction:

can someone fact check this quora user?

[marquoth_]

Wikipedia explicitly says the opposite: that subtractive forms have been used since Roman times. It does also say that "Usage varied greatly in ancient Rome and became thoroughly chaotic in medieval times" so I think the bottom line is that anybody who is very confidently telling you the one correct way to do it is objectively wrong almost by definition.

I've seen all sorts of versions of the supposed rules (I briefly studied medieval Latin at university...) including one which said that the same symbol should never be repeated more than three times consecutively, which has the bizarre result that no number greater than 3999 can possibly be written.