The Problem
“As a Roman Bookkeeper I want to add Roman numbers because doing it manually is too tedious.” Given the Roman numerals, (IVXLCDM which means one, five, ten, fifty, hundred, fivehundred and a thousand respectively), create two numbers and add them. As we are in Rome there is no such thing as decimals or integers, we need to do this with strings. An example would be “XIV” + “LX” = “LXXIV”
There are some rules to a Roman number:
- Numerals can be concatenated to form a larger numeral (“XX” + “II” = “XXII”)
- If a lesser numeral is put before a bigger it means subtraction of the lesser from the bigger (“IV” means four, “CM” means ninehundred)
- If the numeral is I, X or C you can’t have more than three (“II” + “II” = “IV”)
- If the numeral is V, L or D you can’t have more than one (“D” + “D” = “M”)
Clues
- String grouping and concatenation is key to solving this kata. But remember the rule that lesser numerals can preceede bigger ones.
I = 1
IX = 4
V = 5
IX = 9
X = 10
XL = 40
L = 50
XC = 90
C = 100
CD = 400
D = 500
CM = 900
M = 1000
Restrictions
- Try solve the problem with doing any numeric conversion (i.e. you cannot convert the roman numeral to a decimal number)
Examples
Simple Example 1
I + I = II
Simple Example 2
I + II = III
Simple Example 3
V + I = VI
Complex Example
IV + V = IX