Easy
Given an integer num
, repeatedly add all its digits until the result has only one digit, and return it.
Example 1:
Input: num = 38
Output: 2
Explanation: The process is 38 –> 3 + 8 –> 11 11 –> 1 + 1 –> 2 Since 2 has only one digit, return it.
Example 2:
Input: num = 0
Output: 0
Constraints:
0 <= num <= 231 - 1
Follow up: Could you do it without any loop/recursion in O(1)
runtime?
class Solution {
fun addDigits(num: Int): Int {
if (num == 0) {
return 0
}
return if (num % 9 == 0) {
9
} else {
num % 9
}
}
}