LeetCode 258. Add Digits

Description

https://leetcode.com/problems/add-digits/

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

Explanation

Loop until the sum of digits becomes only one digit.

Python Solution

class Solution:
    def addDigits(self, num: int) -> int:
                             
        while len(str(num)) > 1:
            result = 0
            for c in str(num):
                result += int(c)            
            num = result
       
        return num