LeetCode Top Interview 150
202. Happy Number
Easy
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:
a = n
rem = 0
sum_val = 0
if a == 1 or a == 7:
return True
elif 1 < a < 10:
return False
else:
while a != 0:
rem = a % 10
sum_val += rem * rem
a //= 10
if sum_val != 1:
return self.isHappy(sum_val)
else:
return True