Happy Number

Write an algorithm to determine if a number n 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. Repeat the process until the number equals 1 or it loops endlessly in a cycle which does not include 1. If the process ends in 1, the number is happy. Return true if n is a happy number, and false if not.

Constraints

• 1 <= n <= 2^31 - 1