## 问题描述

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

1 | Symbol Value |

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:**

1 | Input: "III" |

**Example 2:**

1 | Input: "IV" |

**Example 3:**

1 | Input: "IX" |

**Example 4:**

1 | Input: "LVIII" |

**Example 5:**

1 | Input: "MCMXCIV" |

**Related Topics:** Math, String

原问题: 13. Roman to Integer

中文翻译版: 13. 罗马数字转整数

## 解决方案

题目难度不大，根据题目描述可以写出代码

1 | #include <iostream> |