202. Happy Number

最新推荐文章于 2024-01-10 13:13:11 发布

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原文链接：http://www.cnblogs.com/sxbjdl/p/5221571.html

本文介绍了一种用于判断正整数是否为快乐数的算法。快乐数是指通过将该数替换为其各位数字的平方和，并重复此过程直到数字变为1的过程中的数。文中提供了一个Python实现的例子，展示了如何通过循环计算直至确定输入数字是否为快乐数。

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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)