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?

problem17_euler.py

singleDigits = ["zero","one","two","three","four","five","six","seven","eight","nine"]

tens = ["zero","ten","twenty","thirty","forty","fifty","sixty","seventy","eighty","ninety"]

teens = ["zero"] * 11 + ["eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen"]

hundredLength = len("hundred")
andLength = len("and")

singleDigits = [len(x) for x in singleDigits]
tens = [len(x) for x in tens]
teens = [len(x) for x in teens]

lengths = []

def getLength(number):
  isTeen = False
  originalNumber = number
  l = []
  if number / 100 > 0:
    l.append(singleDigits[number/100])
    l.append(hundredLength)
    number = number % 100
    if number > 0:
      l.append(andLength)
  if number / 10 > 0:
    if number < 20 and number > 10:
      l.append(teens[number])
      isTeen = True
      number = number % 10
    else:
      l.append(tens[number/10])
      number = number % 10
  if number > 0 and not isTeen:
    l.append(singleDigits[number])

  return sum(l)

for number in xrange(1, 1000):
  lengths.append(getLength(number))


lengths.append(len("one"))
lengths.append(len("thousand"))
print sum(lengths)