258. Add Digits
Description
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?
Solutions
Solution 1
1 2 3 |
|
1 2 3 4 5 |
|
1 2 3 4 5 6 |
|
1 2 3 4 5 6 |
|
1 2 3 4 5 |
|