https://leetcode.com/problems/add-digits/description/
题目
Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.
For example:
Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.
Follow up:
Could you do it without any loop/recursion in O(1) runtime?
题目翻译
题目解析
参考答案
#include <iostream>
using namespace std;
/*
1 1
2 2
3 3
...
8 8
9 9
10 1
11 2
12 3
13 4
...
17 8
18 9
19 1
20 2
21 3
22 4
...
*/
class Solution {
public:
int addDigits(int num)
{
if (num <= 9)
{
return num;
}
else
{
if (num % 9 == 0)
{
return 9;
}
else
{
return num % 9;
}
}
}
};
int main()
{
return 0;
}
