LeetCode之Add Digits

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.

   

    

     

      

     
     

      

       public class Solution {
      
     
    

     

      

     
     

      

          public int getAllSum(int val) {
      
     
    

     

      

     
     

      

       		int sum = 0;
      
     
    

     

      

     
     

      

       		while (val > 0) {
      
     
    

     

      

     
     

      

       			sum += val % 10;
      
     
    

     

      

     
     

      

       			val /= 10;
      
     
    

     

      

     
     

      

       		}
      
     
    

     

      

     
     

      

       		return sum;
      
     
    

     

      

     
     

      

       	}
      
     
    

     

      

     
     

      
	
      
     
    

     

      

     
     

      

       	public  int addDigits(int num) {
      
     
    

     

      

     
     

      

       		if (num <= 0) 
      
     
    

     

      

     
     

      
			return 0;
      
     
    

     

      

     
     

      
		while (num >= 10) {
      
     
    

     

      

     
     

      

       			num = getAllSum(num);
      
     
    

     

      

     
     

      

       		}
      
     
    

     

      

     
     

      

       		return num;
      
     
    

     

      

     
     

      

       	}
      
     
    

     

      

     
     

      

       }