lc-13-roman-to-integer.py

class Solution:
  def romanToInt(self, s: str) -> int:
    numerals = {
      'I': 1,
      'V': 5,
      'X': 10,
      'L': 50,
      'C': 100,
      'D': 500,
      'M': 1000
    }
  
    total = 0
    numeralList = list(s)
    valueOfPreviousNumeral = 0

    for numeral in numeralList:
      valueOfCurrentNumeral = numerals[numeral]
      total += valueOfCurrentNumeral

      if (valueOfPreviousNumeral < valueOfCurrentNumeral):
        total -= valueOfPreviousNumeral*2
      
      valueOfPreviousNumeral = valueOfCurrentNumeral
    return total