LeedCcode 30 day Challenge #2 - Happy Numbers

LeetCode 202 - Happy Numbers

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: 

Input: 19
Output: true
Explanation: 
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1

Detailed Explanation with 2 different methods in following video:

Source: https://crack-coding-interviews.blogspot.com/2020/04/leedccode-30-day-challenge-2-happy.html