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

python实现：

class Solution(object):

    def sqrsum(self, n):#计算平方和

        m = 0

        while n:

            if n < 10:

                n1 = n

            else:

                n1 = n % 10

            m += n1 ** 2

            n = n / 10

        return m

       

    def isHappy(self, n):

        """

        :type n: int

        :rtype: bool

        LN:list of not happy

        tL:tempt list

        """

        LN = []

        tL = []

        while True:

            if n in LN:

                return False

            elif n not in tL:

                tL.append(n)

                n = self.sqrsum(n)

                if n == 1:

                    return True

            else:

                LN.extend(tL)