# nayuki/Project-Euler-solutions

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ec93b13 Dec 27, 2016
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 # # Solution to Project Euler problem 17 # Copyright (c) Project Nayuki. All rights reserved. # # https://www.nayuki.io/page/project-euler-solutions # https://github.com/nayuki/Project-Euler-solutions # # - For the numbers 0 to 19, we write the single word: # {zero, one, two, three, four, five, six, seven, eight, nine, # ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen}. # - For the numbers 20 to 99, we write the word for the tens place: # {twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety}. # Subsequently if the last digit is not 0, then we write the word for the ones place (one to nine). # - For the numbers 100 to 999, we write the ones word for the hundreds place followed by "hundred": # {one hundred, two hundred, three hundred, ..., eight hundred, nine hundred}. # Subsequently if the last two digits are not 00, then we write the word "and" # followed by the phrase for the last two digits (from 01 to 99). # - For the numbers 1000 to 999999, we write the word for the three digits starting at the # thousands place and going leftward, followed by "thousand". Subsequently if the last three # digits are not 000, then we write the phrase for the last three digits (from 001 to 999). def compute(): ans = sum(len(to_english(i)) for i in range(1, 1001)) return str(ans) def to_english(n): if 0 <= n < 20: return ONES[n] elif 20 <= n < 100: return TENS[n // 10] + (ONES[n % 10] if (n % 10 != 0) else "") elif 100 <= n < 1000: return ONES[n // 100] + "hundred" + (("and" + to_english(n % 100)) if (n % 100 != 0) else "") elif 1000 <= n < 1000000: return to_english(n // 1000) + "thousand" + (to_english(n % 1000) if (n % 1000 != 0) else "") else: raise ValueError() ONES = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"] TENS = ["", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"] if __name__ == "__main__": print(compute())