【LeetCode】13. Roman to Integer

Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

题意：把罗马数字转变为数字

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        flag = 0
        sum = 0
        d = {'M':1000, 'D':500, 'C':100, 'L':50, 'X':10, 'V':5, 'I':1}
        for i in s[::-1]:
            t = d[i]
            if t>=flag:
                flag=t
                sum+=t
            else:
                sum-=t
                
        return sum