題目
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
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1
代碼
class Solution(object):
def isHappy(self, n):
"""
:type n: int
:rtype: bool
"""
if n <= 0:
return False
nums = set([n])
while n != 1:
t = 0
while n != 0:
t += (n%10) ** 2
n /= 10
n = t
if n in nums:
return False
else:
nums.add(n)
return True
