AI Interview Prep is optimized for larger screens
Please open this on a laptop or desktop (1024px and wider) to use the full editor, whiteboard, and AI coaching surface.
Understand the problem
Restate the problem precisely. Interviewers reward candidates who pause, define the contract, and name the guarantees before coding.
Given an encoded string, return its decoded string. The encoding rule is: `k[encoded_string]`, where the `encoded_string` inside the square brackets is being repeated exactly `k` times. Note that `k` is guaranteed to be a positive integer. You may assume that the input string is always valid and that the original data does not contain any digits and that digits are only for those repeat numbers, k.
Once you've drafted a response, click Submit for AI review and a senior engineer will critique your reasoning.