2022-06-20
Last updated
Last updated
Roman numerals are represented by seven different symbols: I
, V
, X
, L
, C
, D
and M
.
For example, 2
is written as II
in Roman numeral, just two ones 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 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.
Example 1:
Example 2:
Example 3:
Constraints:
1 <= s.length <= 15
s
contains only the characters ('I', 'V', 'X', 'L', 'C', 'D', 'M')
.
It is guaranteed that s
is a valid roman numeral in the range [1, 3999]
.