应该有比双循环更省时间的方法（in），可惜在客户现场网络不好，就用双循环做了。

 

Success Details  Runtime: 96 ms, faster than 54.32% of Python3 online submissions forRoman to Integer. Memory Usage: 13.4 MB, less than 37.41% of Python3 online submissions for Roman to Integer.  

Submission Detail

3999 / 3999 test cases passed.	Status:  Accepted
Runtime: 96 ms Memory Usage: 13.4 MB	Submitted: 1 minute ago

 

class Solution:
    def romanToInt(self, s: str) -> int:
        romanDict1 = {"CM":900, "CD":400,"XC":90, "XL":40,"IX":9,"IV":4}
        romanList1 = ["CM", "CD","XC", "XL","IX","IV"]
        romanDict2 = {"M": 1000, "D": 500, "C": 100, "L": 50, "X": 10,"V": 5, "I": 1}
        romanList2 = ["M", "D", "C", "L", "X","V", "I"]
        sum =0
        for index in range(len(s) -1):
            for item in range(len(romanList1)):
                if s[index:index +2] ==romanList1[item]:
                    sum += romanDict1[romanList1[item]]
                    s = s[:index] +'00'+ s[index+2:]

        for index in range(len(s)):
            for item in range(len(romanList2)):
                if s[index] ==romanList2[item]:
                    sum += romanDict2[romanList2[item]]
                    s = s[:index] +'0'+ s[index+1:]
        return sum

 48ms：

 

class Solution:
    def romanToInt(self, s: str) -> int:
        RomanDictionary = {"I":1,"V":5, "X":10,"L":50,"C":100,"D":500,"M":1000}
        s = s.replace("IV", "IIII").replace("IX", "VIIII")
        s = s.replace("XL", "XXXX").replace("XC", "LXXXX")
        s = s.replace("CD", "CCCC").replace("CM", "DCCCC")
        Sum = 0
        for Character in s:
            Sum = Sum + RomanDictionary[Character]
        return Sum