< Previous
Next >
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, two is written as II
in Roman numeral, just two one's added together. Twelve is written as, XII
, which is simply X
+ II
. The number twenty seven 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 before V
(5) and X
(10) to make 4 and 9.
X
can be placed before L
(50) and C
(100) to make 40 and 90.
C
can be placed before D
(500) and M
(1000) to make 400 and 900.
Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.
Example 1:
Input: "III"
Output: 3
Example 2:
Input: "IV"
Output: 4
Example 3:
Input: "IX"
Output: 9
Example 4:
Input: "LVIII"
Output: 58
Explanation: L = 50, V= 5, III = 3.
Example 5:
Input: "MCMXCIV"
Output: 1994
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
[Math]
[String]
Similar Questions
- Integer to Roman (Medium)
Hints
Hint 1
I - 1
V - 5
X - 10
L - 50
C - 100
D - 500
M - 1000
Hint 2
Rules:
* If I comes before V or X, subtract 1 eg: IV = 4 and IX = 9
* If X comes before L or C, subtract 10 eg: XL = 40 and XC = 90
* If C comes before D or M, subtract 100 eg: CD = 400 and CM = 900