## Problem:

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.

21124

## Code:The solution may include methods that will be found here: Library.java .

public interface EulerSolution{

public String run();

}
/*
* Solution to Project Euler problem 17
* By Nayuki Minase
*
* http://nayuki.eigenstate.org/page/project-euler-solutions
* https://github.com/nayuki/Project-Euler-solutions
*/

public final class p017 implements EulerSolution {

public static void main(String[] args) {
System.out.println(new p017().run());
}

public String run() {
int sum = 0;
for (int i = 1; i <= 1000; i++)
sum += toEnglish(i).length();
return Integer.toString(sum);
}

private static String[] ONES = {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"};  // Requires 0 <= n <= 9
private static String[] TEENS = {"ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"};
private static String[] TENS = {"twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"};

// Requires 0 <= n <= 99999
private static String toEnglish(int n) {
if (n < 0 || n > 99999)
throw new IllegalArgumentException();

if (n < 100)
return tens(n);
else {
String big = "";
if (n >= 1000)
big += tens(n / 1000) + "thousand";
if (n / 100 % 10 != 0)
big += ONES[n / 100 % 10] + "hundred";

return big + (n % 100 != 0 ? "and" + tens(n % 100) : "");
}
}

// Requires 0 <= n <= 99
private static String tens(int n) {
if (n < 10)
return ONES[n];
else if (n < 20)  // Teens
return TEENS[n - 10];
else
return TENS[n / 10 - 2] + (n % 10 != 0 ? ONES[n % 10] : "");
}

}