The problem sounds vague at first and I spent probably too long trying to figure out what 'reduction' meant before just asking.
Clarify the exact output required (max reduction or full series) and the event ordering (assume chronological). Then iterate through events, maintaining a running sum where recycled adds and waste subtracts, tracking the maximum if needed. Discuss time and space complexity, and consider edge cases like empty stream or ties.
Pro tip: Mention that if the stream is not sorted, you may need to sort by timestamp first, which adds O(n log n) time; if sorted, a single pass suffices. Also, note that the running series can be returned as a list of (timestamp, reduction) pairs.
Ask whether to return the maximum reduction or the full running series, and confirm the event ordering (e.g., chronological).
Explain that reduction is computed as sum of recycled quantities minus sum of waste quantities, updated after each event.
Use a simple running sum variable and, if returning the series, a list to store the running values; if finding max, a variable to track the maximum.
Iterate through events in order, update the running sum based on category, and update the max or append to the series as needed.
State time complexity O(n) for sorted input, O(n log n) if sorting needed, and space O(1) for max or O(n) for series; discuss empty stream, negative reduction, and ties.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.