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

12 + 92 = 82

82 + 22 = 68

62 + 82 = 100

12 + 02 + 02 = 1

public class Solution {

private Set<Integer> num_set = new HashSet<Integer>();

public int getSum(int n) {
int sum = 0;
while(n!=0) {
sum = sum+(n%10)*(n%10);
n = n/10;
}
return sum;
}

public boolean isHappy(int n) {
if(num_set.contains(n)) return false;
else num_set.add(n);
int sum = getSum(n);
if(sum==1) return true;
else return isHappy(sum);
}
}