Find target-heavy sliding windows
Company: Roblox
Role: Machine Learning Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Onsite
Given an integer array `nums`, an integer `target`, and a fixed window size `k`, solve the following two tasks:
1. Return all contiguous subarrays of length `k` that contain at least one occurrence of `target`.
2. Among all contiguous subarrays of length `k`, return the first window that contains the maximum number of occurrences of `target`.
If no length-`k` window contains `target`, return an empty list for part (1) and indicate that no valid window exists for part (2).
Aim for an efficient sliding-window solution.
Quick Answer: This question evaluates array manipulation, counting and efficient algorithm design—focusing on the sliding-window technique for detecting and quantifying target occurrences in fixed-size subarrays, and it measures algorithmic efficiency and complexity reasoning.