❤ Leetcode,python2❤ Convert Roman numerals to integers

Roman numerals contain the following seven characters: I, V, X, L, C, D and M.

Character value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, the Roman numeral 2 is written as II, which is the parallel 1. Write XII as X + II. Write XXVII as XX + V + II.

Usually, the smaller Roman numerals are to the right of the larger numerals. But there are exceptions, for example, 4 is not written as IIII, it’s written as IV. The number 1 is to the left of the number 5 and represents the number 4 when the larger number 5 decreases by 1. Similarly, the number 9 represents IX. This particular rule applies only to the following six situations:

I can be put to the left of V (5) and X (10) to represent 4 and 9. X can be placed to the left of L (50) and C (100) to represent 40 and 90. C can be put to the left of D (500) and M (1000) to represent 400 and 900. Given a Roman numeral, convert it to an integer. Make sure the input is in the range of 1 to 3999.

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        bz = {
        '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
        tiao=0
        for i in range(len(s)):
            if tiao ==1:
                tiao = 0
                continue
            try:
                if s[i]+s[i+1] in bz.keys():
                    res += bz[s[i]+s[i+1]]
                    tiao =1
                else:
                    res += bz[s[i]]
                    tiao =0
            except:
                res += bz[s[i]]
        return res
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