cpp-flashcards/org/study_deck_02/dsa/math-geometry/0012-integer-to-roman.org

#+ANKI_DECK: study_deck_02
* TODO 0012. Integer to Roman :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0012. Integer to Roman][0012. Integer to Roman]]
:END:

Seven different symbols represent Roman numerals with the following values:

 Symbol
 Value

 I
 1

 V
 5

 X
 10

 L
 50

 C
 100

 D
 500

 M
 1000

Roman numerals are formed by appending the conversions of decimal place values from highest to lowest. Converting a decimal place value into a Roman numeral has the following rules:

 - If the value does not start with 4 or 9, select the symbol of the maximal value that can be subtracted from the input, append that symbol to the result, subtract its value, and convert the remainder to a Roman numeral.

 - If the value starts with 4 or 9 use the *subtractive form* representing one symbol subtracted from the following symbol, for example, 4 is 1 (~I~) less than 5 (~V~): ~IV~ and 9 is 1 (~I~) less than 10 (~X~): ~IX~. Only the following subtractive forms are used: 4 (~IV~), 9 (~IX~), 40 (~XL~), 90 (~XC~), 400 (~CD~) and 900 (~CM~).

 - Only powers of 10 (~I~, ~X~, ~C~, ~M~) can be appended consecutively at most 3 times to represent multiples of 10. You cannot append 5 (~V~), 50 (~L~), or 500 (~D~) multiple times. If you need to append a symbol 4 times use the *subtractive form*.

Given an integer, convert it to a Roman numeral.

*Example 1:*

*Input:* num = 3749

*Output:* "MMMDCCXLIX"

*Explanation:*


#+begin_src
3000 = MMM as 1000 (M) + 1000 (M) + 1000 (M)
 700 = DCC as 500 (D) + 100 (C) + 100 (C)
  40 = XL as 10 (X) less of 50 (L)
   9 = IX as 1 (I) less of 10 (X)
Note: 49 is not 1 (I) less of 50 (L) because the conversion is based on decimal places
#+end_src


*Example 2:*

*Input:* num = 58

*Output:* "LVIII"

*Explanation:*


#+begin_src
50 = L
 8 = VIII
#+end_src


*Example 3:*

*Input:* num = 1994

*Output:* "MCMXCIV"

*Explanation:*


#+begin_src
1000 = M
 900 = CM
  90 = XC
   4 = IV
#+end_src


*Constraints:*

 - ~1 <= num <= 3999~

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python :lc-problem 12 :lc-lang python3
class Solution:
    def intToRoman(self, num: int) -> str:
#+end_src

** TODO C++
#+begin_src cpp :lc-problem 12
class Solution {
public:
    string intToRoman(int num) {
        
    }
};
#+end_src