这题很清晰了，人家都好棒奥
class Solution(object):
def numberToWords(self, num):
"""
:type num: int
:rtype: str
"""
to19 = 'One Two Three Four Five Six Seven Eight Nine Ten Eleven Twelve ' \
'Thirteen Fourteen Fifteen Sixteen Seventeen Eighteen Nineteen'.split()
tens = 'Twenty Thirty Forty Fifty Sixty Seventy Eighty Ninety'.split()
def words(n):
if n < 20:
return to19[n-1:n]
if n < 100:
return [tens[n/10-2]] + words(n%10)
if n < 1000:
return [to19[n/100-1]] + ['Hundred'] + words(n%100)
for p, w in enumerate(('Thousand', 'Million', 'Billion'), 1):
if n < 1000**(p+1):
return words(n/1000**p) + [w] + words(n%1000**p)
return ' '.join(words(num)) or 'Zero'
