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 """ st=set() while n not in st: sum = 0 last = n while n: tmp = n % 10; sum += tmp * tmp n /= 10 st.add(last) n = sum if n == 1: return True return False
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