algorithm_math_romanr_to_integer.py

algorithm_math_romanr_to_integer.py

class Solution(object):
    def romanToInt(self, s):
        """
        :type s: str
        :rtype: int
        """
        leng = len(s)
        
        s   = s + ' '
        i   = 0
        res = 0
        while i < leng: 
            ch, nxCh = s[i], s[i+1]
            inc = 1
            if ch == 'M':
                res += 1000
            elif ch == 'C':
                if nxCh == 'M':
                    res += 900
                    inc = 2
                elif nxCh == 'D':
                    res += 400
                    inc = 2
                else: 
                    res += 100
            elif ch == 'D':
                res += 500
            elif ch == 'X':
                if nxCh == 'C':
                    res += 90
                    inc = 2
                elif nxCh == 'L':
                    res += 40
                    inc = 2
                else:
                    res += 10
            elif ch == 'L':
                res += 50
            elif ch == 'I':
                if nxCh == 'X':
                    res += 9
                    inc = 2
                elif nxCh == 'V':
                    res += 4
                    inc = 2
                else:
                    res += 1
            else: # if ch == 'V'
                res += 5;
            i += inc
        return res