273. Integer to English Words [Hard] 数学

273. Integer to English Words

class Solution(object):
    def numberToWords(self, num):
        """
        :type num: int
        :rtype: str
        """
        if num==0:
            return "Zero"
        vocab = {0:"", 1:"One ", 2:"Two ", 3:"Three ", 4:"Four ",
                 5:"Five ", 6:"Six ", 7:"Seven ", 8:"Eight ", 9:"Nine ",
                 10:"Ten ", 11:"Eleven ", 12:"Twelve ", 13:"Thirteen ", 14:"Fourteen",
                 15:"Fifteen ", 16:"Sixteen ", 17:"Seventeen ", 18:"Eighteen ",
                 19:"Nineteen ",
                 20:"Twenty ", 30:"Thirty ", 40:"Forty ", 50:"Fifty ",
                 60:"Sixty ", 70:"Seventy ", 80:"Eighty ", 90:"Ninety ",
                 100:"Hundred ", 1000:"Thousand ", 1000000:"Million ",
                 1000000000:"Billion ", 1000000000000:"Trillion ",
                 1000000000000000:"Quadrillion"}
        cnt = 1
        res = ''
        while num:
            temp = ''
            len3 = num % 1000
            num = num // 1000
            index1 = len3 // 100
            if index1 != 0:
                temp = temp + vocab[index1] + vocab[100]
            len2 = len3 % 100
            if len2 < 20:
                temp = temp + vocab[len2]
            else:
                a = len2 % 10
                b = len2 - a
                temp = temp + vocab[b] + vocab[a]
            if cnt == 1:
                add = ''
            else:
                add = vocab[cnt]
            if temp:
                temp = temp + add
            cnt *= 1000
            res = temp + res
        return res.strip()