Happy Number
A "Happy Number" is defined as a number that after finite number of "steps" - where
we sum the square of each digit each time - the result is a 1. Given a number n,
determine whether it is a happy number.
As a challenge, complete this question under constant space.
Parameters
n: The number to check.
Result
trueorfalse, depending on whether this number is a happy number.
Examples
Example 1
Input: n = 19
Output: true
Explanation:
1^2 + 9^2 = 82 8^2 + 2^2 = 68 6^2 + 8^2 = 100 1^2 + 0^2 + 0^2 = 1
Example 2
Input: n = 2
Output: false
Explanation:
2^2 = 4 4^2 = 16 1^2 + 6^2 = 37 3^2 + 7^2 = 58 5^2 + 8^2 = 89 8^2 + 9^2 = 145 1^2 + 4^2 + 5^2 = 42 4^2 + 2^2 = 20 2^2 + 0^2 = 4 ...
Constraints
1 <= n < 2^31