[Solved] Given an integer num, repeatedly add all its digits until the result has only one digit, and return it.

Table of Contents

Question

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

Follow up: Could you do it without any loop/recursion in O(1) runtime?

Python Solution

class Solution:
    def addDigits(self, n: int) -> int:
        if n==0:
            return 0
        if n%9==0:
            return 9
        else:
            return n%9
Abhishek Sharma
Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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