class Solution(object):

    def romanToInt(self, s):

        """

        :type s: str

        :rtype: int

        """

        dic = {'I':1,'V':5,'X':10,'L':50,'C':100,'D':500,'M':1000,'IV':4,'IX':9,'XL':40,'XC':90,'CD':400,'CM':900}

        res = 0

        flag = 0

        for i in range(len(s)-1):

            if flag:

                flag = 0

                continue

            temp = s[i] + s[i+1]

            if temp in dic:

                res += dic[temp]

                flag = 1

            else:

                res += dic[s[i]]

        if flag == 0:

            return res + dic[s[-1]]

        return res
                           

class Solution(object):

    def romanToInt(self, s):

        """

        :type s: str

        :rtype: int

        """

        roman_map = {

            "I": 1,

            "V": 5,

            "X": 10,

            "L": 50,

            "C": 100,

            "D": 500,

            "M": 1000

        }

        sum = 0

        for idx, c in enumerate(s[:-1]):

            num = roman_map[c]

            sum +=  (-num) if roman_map[s[idx+1]] > num else num#题目已经说了字母是按大到小,除了特殊的

        sum += roman_map[s[-1]]

        return sum