CodingEasycod-g948

Subject MathLevel Entry–Mid~10 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a non-negative integer n, repeatedly replace it with the sum of its digits until a single digit (0-9) remains, then return that digit. For example 38 -> 3+8=11 -> 1+1=2. n fits in a normal integer.

Implement

digit_root(n: int) → int

Examples

in[38]out2

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.