202. Happy Number

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

class Solution(object):
    def isHappy(self, n):
        """
        :type n: int
        :rtype: bool
        """
        def fun(num):
            s = str(num)
            v = 0
            for x in s:
                v += (int(x) - int('0')) * (int(x) - int('0'))
            return v
        if n <= 0:
            return False;
        d = {};
        while(True):
            if n == 1:
                return True
            if n in d.keys():
                return False
            else:
                d[n] = 1
                n = fun(n)