# LeetCode — Roman to Integer

Roman numerals are represented by seven different symbols: `I`, `V`, `X`, `L`, `C`, `D` and `M`.

`Symbol       ValueI             1V             5X             10L             50C             100D             500M             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 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:

`Input: s = "III"Output: 3`

Example 2:

`Input: s = "IV"Output: 4`

Example 3:

`Input: s = "IX"Output: 9`

Example 4:

`Input: s = "LVIII"Output: 58Explanation: L = 50, V= 5, III = 3.`

Example 5:

`Input: s = "MCMXCIV"Output: 1994Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.`

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]`.

Solution:

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Dell Technologies — VxRail Software Engineer 👨‍💻

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## Steven Lu

Dell Technologies — VxRail Software Engineer 👨‍💻