13. Roman to Integer - LeetCode Solution

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