[Leetcode][python]Roman to Integer/罗马数字转整数

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        table = {'M':1000, 'CM':900, 'D':500, 'CD':400, 'C':100, 'XC':90, 'L':50, 'XL': 40, 'X':10, 'IX':9, 'V':5, 'VI':4, 'I':1}
        result = 0
        for i in range(len(s)):
            if i > 0 and table[s[i]] > table[s[i-1]]:
                result += table[s[i]]
                result -= 2 * table[s[i-1]]
            else:
                result += table[s[i]]
        return result