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.
n is a happy number, and
false if not.
Input: n = 19 Output: true Explanation: 12 + 92 = 82 82 + 22 = 68 62 + 82 = 100 12 + 02 + 02 = 1
Input: n = 2 Output: false
1 <= n <= 231 - 1
Solution in python
class Solution: def isHappy(self, n: int) -> bool: def digitSum(n): return sum(map(lambda x:x*x, map(int,list(str(n))))) seen = set() while not n in seen: seen.add(n) n = digitSum(n) if n == 1: return True return False