글자 수 세기

1부터 1000까지를 영어로 썼을 때, 전부 다 쓰려면 영어 몇 글자가 필요한가?

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?

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.

원문 : http://projecteuler.net/index.php?section=problems&id=17

one

two
three
four
five
six
seven
eight
nine = 36
ten
eleven
twelve
thirteen
fourteen
fifteen
sixteen
seventeen
eighteen
nineteen = 70
twenty = 6*10 + 36
thirty = 6*10 + 36
forty = 5*10 + 36
fifty = 5*10 + 36
sixty = 5*10 + 36
seventy = 7*10 + 36
eighty = 6*10 + 36
ninety = 6*10 + 36

36*9 + 70 = 394

460
854

one hundred = 10*100
two hundred = 10*100
three hundred = 12*100
four hundred = 11*100
five hundred = 11*100
six hundred = 10*100
seven hundred = 12*100
eight hundred = 12*100
nine hundred = 11*100

99*100=9900
854*10=8540

and = 3*99*9

one thousand = 11