[leetcode: Python]202.Happy Number

题目：
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

1^2 + 9^2 = 828^2 + 2^2 = 686^2 + 8^2 = 1001^2 + 0^2 + 0^2 = 1

方法一：性能58ms

class Solution(object):    def isHappy(self, n):        """        :type n: int        :rtype: bool        """        if n == 1:            return True        if n == 4:            return False        s = str(n)        m = []        a = 0        for i in s:            m.append(int(i))        for i in m:            a += i**2        n = a        return self.isHappy(n)

方法二：性能39ms

sample 39 ms submissionclass Solution(object):    def isHappy(self, n):        """        :type n: int        :rtype: bool        """        res = 0        while n:            res = res + (n % 10)**2            n /= 10          n = res            return self.isHappy(n) if n > 4 else n ==1