## Little Puzzlers–Positive Integer to Roman Numerals

*I like to keep my brain sharp by working on programming puzzlers. On off weeks I'm going to start posting programming puzzlers I've collected over the years. Hopefully you'll find them as entertaining as I do.*

There’s really no “ah-hah!” moment with this problem, but it is still – I find – a good programming problem for seeing how well a candidate’s mind works in structuring logic and finding patterns.

### The Problem

Given a positive integer (i.e. > 0), please return a string representation of that integer using Roman Numerals. You may assume IV for four, though you can optionally use IIII if you prefer the standard clock representation of 4.

Interesting side note: some say that the reason IIII is used instead of IV on clocks is because IV represented the Roman god Jove, and thus was omitted from the clock face to avoid “blasphemy”.

If you’re not familiar with Roman Numerals, you can find a good primer nearly anywhere on the internet (such as __here__ on Wikipedia), though the basics are:

- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000

Roman numerals are generally written from highest denominate to lowest denomination, except where the previous “unit” letter is used to create 1 of the previous “unit” less than the next.

- I can be placed before V and X to make 4 (IV) and 9 (IX) respectively
- X can be placed before L and C to make 40 (XL) and 90 (XC) respectively
- C can be placed before D and M to make 400 (CD) and 900 (CM) respectively.

Note that V, L, and D are not used to prefix the next number since this would obviously be redundant (i.e. VX is the same as V, LC is the same as L).

### Spoiler Alert!

**Fair Warning:** there may be discussion of the problem and potential solutions posted in the comments below. Read at your own risk.

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Print | posted on Tuesday, May 5, 2015 2:48 AM |