CodingMediumcod-g822

Subject String parsingLevel Mid–Senior~28 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Decode a string with nested run-length encoding of the form k[encoded] meaning the bracketed content repeated k times, where k is a positive integer and content may itself contain nested k[...] groups and lowercase letters. For '3[a2[c]]' return 'accaccacc'. The decoded output fits comfortably in memory; input length up to a few thousand.

Implement

decode_string(s: str) → str

Examples

in["3[a2[c]]"]out"accaccacc"

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.