258. Add Digits (Easy)
https://leetcode.com/problems/add-digits/
Given a non-negative integer num
, repeatedly add all its digits until the result has only one digit.
Example:
Input:38
Output: 2 Explanation: The process is like:3 + 8 = 11
,1 + 1 = 2
. Since2
has only one digit, return it.
Follow up:
Could you do it without any loop/recursion in O(1) runtime?
Solutions
- Java
https://www.cnblogs.com/grandyang/p/4741028.html
class Solution {
// write done the numbers and you are able to discover the pattern readily.
public int addDigits(int num) {
return (num == 0) ? 0 : (num - 1) % 9 + 1;
}
}