Leetcode:13- Roman to Integer

 1 class Solution(object):
 2     def romanToInt(self,s):
 3         d = {‘I‘:1,‘V‘:5,‘X‘:10,‘L‘:50,‘C‘:100,‘D‘:500,‘M‘:1000}  #字典记录
 4         sum = d[s[len(s)-1]]   #这里是从右往左，从左往右也可
 5         for i in range(len(s)-1,0,-1):  #相邻两个比大小
 6             r = d[s[i]]
 7             l = d[s[i-1]]
 8             if l >= r:   #高位在左边，加
 9                 sum += l
10             else:        #高位在右边，减
11                 sum -= l
12         return sum
13 if __name__==‘__main__‘:
14     solution = Solution()
15     s = ‘VII‘
16     print(solution.romanToInt(s))