每日kata~03-[github搬家]

时隔多年终于写出来一个递归，小开心0v0

题目：

https://www.codewars.com/kata/541c8630095125aba6000c00

In this kata, you must create a digital root function.

A digital root is the recursive sum of all the digits in a number. Given n, take the sum of the digits of n. If that value has more than one digit, continue reducing in this way until a single-digit number is produced. This is only applicable to the natural numbers.

Here's how it works:

digital_root(16)
=> 1 + 6
=> 7

digital_root(942)
=> 9 + 4 + 2
=> 15
=> 1 + 5
=> 6

digital_root(132189)
=> 1 + 3 + 2 + 1 + 8 + 9
=> 24 ...
=> 2 + 4
=> 6

digital_root(493193)
=> 4 + 9 + 3 + 1 + 9 + 3
=> 29 ...
=> 2 + 9
=> 11 ...
=> 1 + 1
=> 2

解：

public static int digital_root(int n) {
    // ...
    int sum = 0;
    int ten = 10;
    int i = 0;
    do {
        int b = n%ten;
        n = n/10;
        if(i>5)
            i = 0;
        
        sum += b;
        //System.out.println(sum);
        i++;
                
    }while(n>0);
    
    if(sum>=10) {
        sum = digital_root(sum);
    }

    
    //System.out.println(sum);
    return sum;
  }