Happy Number

Write an algorithm to determine if a number is “happy”.
A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.
Example: 19 is a happy number
1^2 + 9^2 = 82
8^2 + 2^2 = 68
6^2 + 8^2 = 100
1^2 + 0^2 + 0^2 = 1
Solution:
1. public class Solution {
2. public boolean isHappy(int n) {
3. Set set = new HashSet();
4. 5. while (n > 1) {
6. int m = 0;
7. 8. while (n > 0) {
9. int d = n % 10;
10. m += d * d;
11. n /= 10;
12. }
13. 14. if (set.contains(m))
15. return false;
16. 17. set.add(m);
18. 19. n = m;
20. }
21. 22. return true;
23. }
24. }