Day20# Leetcode - Roman to Integer

第 20 天的 Leetcode 要开始拉，那我们就开始吧 ─=≡Σ(((っ›´ω`‹ )っ！

今天要写的题目是 Roman to Integer，顾名思义就是把罗马数字转换成一般常见的阿拉伯数字。

Example:

Input: s = "III"
Output: 3

Input: s = "IV"
Output: 4

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

困难的点是必须要去判断像 IV 这种由两个字组成的值。

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.

结尾

怕超过时间，先待补