Happy Number

07/16/2016 Hash Table Math


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


Result: Accepted Time: 52 ms

Here should be some explanations.

class Solution(object):
    def isHappy(self, n):
        :type n: int
        :rtype: bool
        while n not in st:
            sum = 0
            last  = n
            while n:
                tmp = n % 10;
                sum += tmp * tmp
                n /= 10
            n = sum
            if n == 1:
                return True
        return False

Complexity Analytics

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