Write an algorithm to determine if a number n
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.
- 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.
Return true
if n
is a happy number, and false
if not.
Example 1:
Input: n = 19
Output: true
Explanation:
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1
Example 2:
Input: n = 2
Output: false
Constraints:
-
1 <= n <= 231 - 1
SOLUTION:
class Solution:
def isHappy(self, n: int) -> bool:
visited = set()
while n != 1:
if n in visited:
return False
visited.add(n)
nn = 0
while n != 0:
c = n % 10
nn += c * c
n = n // 10
n = nn
return True
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