[LeetCode&Python] Problem 202. Happy Number

Posted 2021-01-28 chiyeung

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

class Solution(object):
    def isHappy(self, n):
        """
        :type n: int
        :rtype: bool
        """
        ne=0
        while n>6:
            while n//10>0:
                ne+=(n%10)**2
                n=n//10
            ne+=n**2
            n=ne
            ne=0
        return n==1