202. Happy Number Leetcode Python

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

Credits:
Special thanks to @mithmatt and @ts for adding this problem and creating all test cases.

This algorithm need to validate its digits.

class Solution:
    # @param {integer} n
    # @return {boolean}
    def isHappy(self, n):
        val = set()
        while n not in val:
            val.add(n)
            newn = 0
            while n != 0:
                newn +=  (n % 10) * (n % 10)
                n /=  10
            n = newn
            if n == 1:
                return True
        return False

原文：http://blog.csdn.net/hyperbolechi/article/details/45454309