Cracking the Coding Interview, 4 Edition - 150 Programming Interview Questions and Solutions

Solutions to Chapter 19 | Moderate
19.6 Given an integer between 0 and 999,999, print an English phrase that describes the
integer (eg, “One Thousand, Two Hundred and Thirty Four”).
SOLUTION
pg 89
This is not an especially challenging problem, but it is a long and tedious one. Your interviewer
is unlikely to ask to see every detail, but he / she will be interested in how you approach
the problem.
1 public static String numtostring(int num) {
2 StringBuilder sb = new StringBuilder();
3
4 // Count number of digits in num.
5 int len = 1;
6 while (Math.pow((double)10, (double)len ) < num) {
7 len++;
8 }
9
10 String[] wordarr1 = {“”,”One ”, “Two ”, “Three ”, “Four ”,
11 “Five ”, “Six ”, “Seven ”, “Eight ”,”Nine ”};
12 String[] wordarr11 = {“”, “Eleven ”, “Twelve ”, “Thirteen ”,
13 “Fourteen ”, “Fifteen ”, “Sixteen ”,
14 “Seventeen ”, “Eighteen ”, “Nineteen ”};
15 String[] wordarr10 = {“”,”Ten ”, “Twenty ”, “Thirty ”, “Forty ”,
16 “Fifty ”, “Sixty ”, “Seventy ”, “Eighty ”,
17 “Ninety “};
18 String[] wordarr100 = {“”, “Hundred ”, “Thousand ”};
19 int tmp;
20 if (num == 0) {
21 sb.append(“Zero”);
22 } else {
23 if (len > 3 && len % 2 == 0) {
24 len++;
25 }
26 do {
27 // Number greater than 999
28 if (len > 3) {
29 tmp = (num / (int)Math.pow((double)10,(double)len-2));
30 // If tmp is 2 digit number and not a multiple of 10
31 if (tmp / 10 == 1 && tmp%10 != 0) {
32 sb.append(wordarr11[tmp % 10]) ;
33 } else {
34 sb.append(wordarr10[tmp / 10]);
35 sb.append(wordarr1[tmp % 10]);
36 }
2 7 1
Cracking the Coding Interview | Additional Review Problems