Leetcode13.py

class Solution:
    def romanToInt(self, s: str) -> int:
        roman_dic = {'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M':1000}
        str_lenth=len(s)
        res=0
        for i in range(str_lenth):
            if i<str_lenth-1 and roman_dic[s[i]]<roman_dic[s[i+1]]:
                res-=roman_dic[s[i]]
            else:
                res+=roman_dic[s[i]]
        return res