整数转罗马数字 python

原文链接

一个容易理解的方法

class Solution(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        tmp = []
        roman = ''
        if not num:
            raise ValueError

        while num >= 1000:
            num -= 1000
            tmp.append('M')

        while num >= 900:
            num -= 900
            tmp.append('CM')

        while num >= 500:
            num -= 500
            tmp.append('D')

        while num >= 400:
            num -= 400
            tmp.append('CD')

        while num >= 100:
            num -= 100
            tmp.append('C')

        while num >= 90:
            num -= 90
            tmp.append('XC')

        while num >= 50:
            num -= 50
            tmp.append('L')

        while num >= 40:
            num -= 40
            tmp.append('XL')

        while num >= 10:
            num -= 10
            tmp.append('X')

        while num >= 9:
            num -= 9
            tmp.append('IX')

        while num >= 5:
            num -= 5
            tmp.append('V')

        while num >= 4:
            num -= 4
            tmp.append('IV')

        while num >= 1:
            num -= 1
            tmp.append('I')

        return roman.join(tmp)

class Solution(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        tmp = []
        hashmap = {'I': 1, 'IV': 4, 'IX': 9, 'XL': 40, 'XC': 90, 'CD': 400, 'CM': 900, 'V': 5,
                   'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
        sort_hashmap = sorted(hashmap.items(), key=lambda _: _[1], reverse=True)
        roman = ''
        for i in range(len(sort_hashmap)):
            while num>=sort_hashmap[i][1]:
                num -= sort_hashmap[i][1]
                tmp.append(sort_hashmap[i][0])
        return roman.join(tmp)