LeetCode 13 – Python 3 (Week 5 – 04)

class Solution:
    def romanToInt(self, s: str) -> int:
        number_map, ans = {'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M': 1000}, 0
        
        for i in range(len(s)):
            if i > 0 and number_map[s[i]] > number_map[s[i-1]]:
                ans += number_map[s[i]] - 2*number_map[s[i-1]]
            else: ans += number_map[s[i]]
                
        return ans