Roman to Integer Leetcode Python

Given a Roman numeral, convert it to an integer.

Input is guaranteed to being within the range from 1 to 3999.

The practice of this problem and the previous one interger to Roman similar to build a dictionary to query.

1. Reverse the string first

2. Use one last to save the previous digit

3. If the last digit is greater than the current digit, subtract the value by twice times digit otherwise add.

For example, iv inversion is the VI direct plus after equals 6 actual value of 4 need to subtract twice times 1

The code is as follows

Class solution:    # @return An integer    def romantoint (self, s):        dict={' M ': +, ' D ': $, ' C ': +, ' L ': ' X ' : Ten, ' V ': 5, ' I ': 1}        last=none        sum=0        s=s[::-1] for        Elem in S:            if Last and Dict[last]>dict[elem]:                Sum-=2*dict[elem]            Sum+=dict[elem]            last=elem        return sum                        

Reference http://www.cnblogs.com/zuoyuan/p/3779688.html

Roman to Integer Leetcode Python