【LeetCode】 202. 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 {
public boolean isHappy(int n) {
HashSet<Integer> hs = new HashSet<Integer>();
while (hs.add(n)) {
int sum = 0;
while (n > 0) {
int temp = n % 10;
sum += temp * temp;
n = n / 10;
}
if (sum == 1) {
return true;
} else {
n = sum;
}
}
return false;
}
}