leetcode

0 class Solution {

1 static string int_string(int n) {

2 static const char *const below_20[] = {"One", "Two", "Three", "Four", "Five",

3 "Six", "Seven", "Eight", "Nine", "Ten",

4 "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen",

5 "Sixteen", "Seventeen", "Eighteen", "Nineteen"};

6 static const char *const below_100[] = {"Twenty", "Thirty", "Forty", "Fifty",

7 "Sixty", "Seventy", "Eighty", "Ninety"};

8

9 if (n >= 1000000000)

10 return int_string(n / 1000000000) + " Billion" + int_string(n - 1000000000 * (n / 1000000000));

11 else if (n >= 1000000)

12 return int_string(n / 1000000) + " Million" + int_string(n - 1000000 * (n / 1000000));

13 else if (n >= 1000)

14 return int_string(n / 1000) + " Thousand" + int_string(n - 1000 * (n / 1000));

15 else if (n >= 100)

16 return int_string(n / 100) + " Hundred" + int_string(n - 100 * (n / 100));

17 else if (n >= 20)

18 return string(" ") + below_100[n / 10 - 2] + int_string(n - 10 * (n / 10));

19 else if (n >= 1)

20 return string(" ") + below_20[n - 1];

21

22 return "";

23 }

24

25 public:

26 string numberToWords(int num) const {

27 if (num == 0) return "Zero";

28 return int_string(num).substr(1);

29 }

30 };