chal_202.py

class Solution(object):
    def sum_of_squares(self, n):
        result = 0
        while n > 0:
            digit = n % 10
            n = n // 10
            result += digit ** 2
        return result

    def is_happy(self, n):
        """
        :type n: int
        :rtype: bool
        """
        visited = set()

        while n != 1 and n not in visited:
            visited.add(n)
            n = self.sum_of_squares(n)

        return n == 1


# Test cases
sol = Solution()

n = 19
assert sol.is_happy(n)

n = 2
assert not sol.is_happy(n)