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Section 1Understand Problem
Section 01
Understand the problem
Restate the problem precisely. Interviewers reward candidates who pause, define the contract, and name the guarantees before coding.
Problem statement
Given an integer `num`, repeatedly add all its digits until the result has only one digit, and return it.
Example
num = 38 → 2
Constraints
0 ≤ num ≤ 2³¹ − 1
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WPM—Fillers0Pace—Thinking0%
Explain the problem in your own words
0 words0 chars
AI Review
Write your thinking above first.
Once you've drafted a response, click Submit for AI review and a senior engineer will critique your reasoning.
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The reviewer will check whether you stated inputs, output, guarantees, and any assumption you flagged.
Write at least a couple of sentences explaining the problem before submitting.