Easy
Write an algorithm to determine if a number n
is happy.
A happy number is a number defined by the following process:
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
function isHappy(n: number): boolean {
let a = n
let rem: number
let sum = 0
if (a === 1 || a === 7) {
return true
} else if (a > 1 && a < 10) {
return false
} else {
while (a !== 0) {
rem = a % 10
sum += rem * rem
a = Math.floor(a / 10)
}
return sum === 1 ? true : isHappy(sum)
}
}
export { isHappy }