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) { Set data = new HashSet(); int result = 0; while (true) { result = compute(n); if (result == 1) return true; if (data.contains(result)) { break; } else { data.add(result); } n = result; } return false; } private int compute(int n) { int result = 0; while (n>0) { int num = n%10; result += num * num; n /= 10; } return result; } }