Roman numerals are represented by seven different symbols: I
, V
, X
, L
, C
, D
and M
.
Symbol Value
I 1
V 5
X 10
L 50
C 100
D 500
M 1000
For example, 2
is written as II
in Roman numeral, just two one's added together. 12
is written as XII
, which is simply X + II
. The number 27
is written as XXVII
, which is XX
+ V
+ II
.
Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII
. Instead, the number four is written as IV
. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX
. There are six instances where subtraction is used:
I
can be placed beforeV
(5) and X (10) to make 4 and 9.X
can be placed beforeL
(50) and C (100) to make 40 and 90.C
can be placed beforeD
(500) and M (1000) to make 400 and 900.
Given an integer, convert it to a roman numeral.
Input: num = 3
Output: "III"
Input: num = 4
Output: "IV"
Input: num = 9
Output: "IX"
Input: num = 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.
Input: num = 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
1 <= num <= 3999
class Solution:
def intToRoman(self, num: int) -> str:
value = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
syb = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"]
ans = ''
for i in range(len(value)):
for _ in range(num // value[i]):
ans += syb[i]
num %= value[i]
return ans
Simple math-string conversion.