Code Room
CodingHardcod-g390
Subject StringsLevel Senior–Staff~35 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a non-empty string s of lowercase letters (1 <= len(s) <= 10^5), return the starting index i (0 <= i < len(s)) such that the rotation s[i:] + s[:i] is lexicographically smallest. If several indices give the same smallest rotation, return the smallest such index.

Implement
smallest_rotation_index(s: str) → int
Examples
in["bbaaccaadd"]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.

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.