Leetcode 13: Roman to Integer

 

Code

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        pre = 0
        sum = 0
        mapping = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000} 
        for ch in s[::-1]:
            i = mapping[ch]
            if i >= pre:
                sum += i
            else:
                sum -= i
            pre = i

        return sum

 

Idea

Fun to know how to read Roman number!

 

Reference: 

https://discuss.leetcode.com/topic/821/my-solution-for-this-question-but-i-don-t-know-is-there-any-easier-way/2 (Answer from vera_qing)