Happy Number

A happy number is a number which yields a 1 by repeatedly summing up the square of its digits. If such a process results in an endless cycle of numbers containing 4, the number is said to be an unhappy number.

Create a function that accepts a number and determines whether the number is a happy number or not. Return true if so, false otherwise.

Examples

isHappy(67) ➞ false

isHappy(89) ➞ false

isHappy(139) ➞ true

isHappy(1327) ➞ false

isHappy(2871) ➞ false

isHappy(3970) ➞ true

Notes

• Hint: Your loop terminates if the value of n is either 1 or 4.
• Optionally, you can solve this challenge via a recursive approach.
• A recursive version of this challenge can be found here.