human
Solve in Python:
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
assistant
#Here is Python program to determine if a number is "happy".

class Solution:
     def isHappy(self, n):
         """
         :type n: int
         :rtype: bool
         """
         def next(n):
             res = 0
             while n > 0:
                 n, lsd = n // 10, n % 10
                 res += lsd * lsd
             return res
         
         seen = set()
         while True:
             seen.add(n)
             n = next(n)
             if n == 1:
                 return True
             if n in seen:
                 return False