Problem 17

Problem Statement :Problem17

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.

Algorithm:

• The algorithm for this problem is brute.
• Numbers with length 2 have been broken into their corresponding units and tens places
• Similarly number with 3 digits have been broken into their corresponding hundreds,units and tens places.
• Then we use the same function to reuse the broken numbers and extract the corresponding number name.

Solution:

public class problem17_1 {
 public static String numberTransfer(int number) {
  String s = null;

  if (number <= 19 && number >= 1) {
   switch (number) {
   case 1:
    s = "one";
    break;
   case 2:
    s = "two";
    break;
   case 3:
    s = "three";
    break;
   case 4:
    s = "four";
    break;
   case 5:
    s = "five";
    break;
   case 6:
    s = "six";
    break;
   case 7:
    s = "seven";
    break;
   case 8:
    s = "eight";
    break;
   case 9:
    s = "nine";
    break;
   case 10:
    s = "ten";
    break;
   case 11:
    s = "eleven";
    break;
   case 12:
    s = "twelve";
    break;
   case 13:
    s = "thirteen";
    break;
   case 14:
    s = "fourteen";
    break;
   case 15:
    s = "fifteen";
    break;
   case 16:
    s = "sixteen";
    break;
   case 17:
    s = "seventeen";
    break;
   case 18:
    s = "eighteen";
    break;
   case 19:
    s = "nineteen";
    break;
   }
  } else if (number == 20) {
   s = "twenty";
  } else if (number >= 20 && number <= 29) {
   number -= number / 10 * 10;
   s = "twenty-" + numberTransfer(number);
  } else if (number == 30) {
   s = "thirty";
  } else if (number >= 31 && number <= 39) {
   number -= number / 10 * 10;
   s = "thirty-" + numberTransfer(number);
  } else if (number == 40) {
   s = "forty";
  } else if (number >= 41 && number <= 49) {
   number -= number / 10 * 10;
   s = "forty-" + numberTransfer(number);
  } else if (number == 50) {
   s = "fifty";
  } else if (number >= 51 && number <= 59) {
   number -= number / 10 * 10;
   s = "fifty-" + numberTransfer(number);
  } else if (number == 60) {
   s = "sixty";
  } else if (number >= 61 && number <= 69) {
   number -= number / 10 * 10;
   s = "sixty-" + numberTransfer(number);
  } else if (number == 70) {
   s = "seventy";
  } else if (number >= 71 && number <= 79) {
   number -= number / 10 * 10;
   s = "seventy-" + numberTransfer(number);
  } else if (number == 80) {
   s = "eighty";
  } else if (number >= 81 && number <= 89) {
   number -= number / 10 * 10;
   s = "eighty-" + numberTransfer(number);
  } else if (number == 90) {
   s = "ninety";
  } else if (number >= 91 && number <= 99) {
   number -= number / 10 * 10;
   s = "ninety-" + numberTransfer(number);
  } else if (number == 100 || number == 200 || number == 300
    || number == 400 || number == 500 || number == 600
    || number == 700 || number == 800 || number == 900) {
   number /= 100;
   s = numberTransfer(number) + " hundred";
  } else if (number >= 101 && number <= 999) {
   int h = number / 100;
   number = number - h * 100;
   s = numberTransfer(h) + " hundred and " + numberTransfer(number);
  } else if (number == 1000) {
   s = "one thousand";
  } else if (number >= 1000 && number <= 9999) {
   int t = number / 1000;
   number = number - t * 1000;
   s = numberTransfer(t) + " thoustand " + numberTransfer(number);
  } else {
   s = "ERROR";
  }

  return s;
 }

 public static void main(String[] args) {
  int result = 0;
  String s;

  for (int i = 1; i <= 1000; i++) {
   s = numberTransfer(i);
   for (int j = 0; j < s.length(); j++) {
    if (s.charAt(j) != ' ' && s.charAt(j) != '-') {
     result++;
    }
   }
  }
  System.out.println(result);
 }
}

After-Thought:

The problem doesnt involve any aspect of numbers as such just breaking them and using a large number of special cases to generate the answer.