Happy Number
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 include1. - 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 = 19Output
trueStarting from 19, the digit-square-sum sequence is 82, then 68, then 100, then 1, so 19 is happy.
Example 2
Input
n = 2Output
falseStarting from 2, the process does not end in 1, so 2 is not happy.
Constraints
- 1 <= n <= 2^31 - 1