Project Euler 第17题

If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.

If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?
求1-1000英文单词字母数之和

NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of "and" when writing out numbers is in compliance with British usage.

分析：先求1..99单词总个数。

然后求：sum(len(one)+len(two)+..+len(nine))*100+len(hunderd)*900+len(and)*99*9+sum(1..99)*10+len（one thousand）