I was not able to locate any reliable public source that contains a Citadel interview problem explicitly titled “Disk Space Analysis” with the exact combination of tags Sliding Window, Monotonic Queue, and Deque, along with a full official statement, constraints, and examples.[1][2][4][7][9][10]
Problems that match the technique (sliding window + monotonic deque) and are often used in interviews—including at top trading and tech firms—look very similar to classic “sliding window maximum / minimum” style questions, for example LeetCode 239 (Sliding Window Maximum) or variants where you compute statistics over all contiguous subarrays of a fixed length using a monotonic deque. There is also a known Citadel OA problem “Global Maximum” that is a sliding-window-like subsequence maximum problem, but it is distinct and not labeled “Disk Space Analysis.”[7][9][10][1]
Because I cannot access the exact proprietary Citadel text and there is no authoritative public mirror of a problem with this precise name and tag set, I cannot truthfully reconstruct its full official wording, constraints, and all examples. Any attempt to “recreate” the problem statement would be a guess and could mislead you in preparation for the interview.
If you want, I can instead:
Tell me if that kind of practice-oriented reconstruction is acceptable, and if you have any hints about the original (e.g., “find max free space in any window of size k”), I can tailor it even closer to what you likely saw.