romanToInt.txt

my:
class Solution:
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        str_max = len(s)
        output = 0
        counter = 0
        while counter <= str_max-1:
            if s[counter] == "I":
                if counter != str_max-1 and s[counter+1] == "V":
                    output += 4
                    counter += 2
                elif counter != str_max-1 and s[counter+1] == "X":
                    output += 9
                    counter += 2
                else:
                    output += 1
                    counter += 1
                    
            elif s[counter] == "X":
                if counter != str_max-1 and s[counter+1] == "L":
                    output += 40
                    counter += 2
                elif counter != str_max-1 and s[counter+1] == "C":
                    output += 90
                    counter += 2
                else:
                    output += 10
                    counter += 1
            
            elif s[counter] == "C":
                if counter != str_max-1 and s[counter+1] == "D":
                    output += 400
                    counter += 2
                elif counter != str_max-1 and s[counter+1] == "M":
                    output += 900
                    counter += 2
                else:
                    output += 100
                    counter += 1
            
            elif s[counter] == "V":
                output += 5
                counter += 1
            elif s[counter] == "L":
                output += 50
                counter += 1
            elif s[counter] == "D":
                output += 500
                counter += 1
            elif s[counter] == "M":
                output += 1000
                counter += 1
                
        return output


updated:
class Solution:
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        if not s:
            return 0
        hmap = {
            'I': 1,
            'V': 5,
            'X': 10,
            'L': 50,
            'C': 100,
            'D': 500,
            'M': 1000
        }
        ans = hmap[s[-1]]
        for i in range(len(s)-2, -1, -1):
            if hmap[s[i]] < hmap[s[i+1]]:
                ans -= hmap[s[i]]
            else:
                ans += hmap[s[i]]
        return ans