Add the digits until one digit remains
Coding problemEasyAsked in: Zupee
Given a non-negative integer n, add up its digits. If the result has more than one digit, add up its digits again. Repeat until a single digit remains, and return it.
For 38: 3 + 8 = 11, then 1 + 1 = 2, so the answer is 2.
Examples
Example 1
Input: n = 38
Output: 2
Example 2
Input: n = 0
Output: 0
Example 3
Input: n = 9875
Output: 2
9 + 8 + 7 + 5 = 29, 2 + 9 = 11, 1 + 1 = 2.
Constraints
- n is between 0 and 2,147,483,647
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