Find top/bottom-k words in list or stream

You are given words (strings) either as a finite list or as an unbounded stream. 1) **List version**: Given an array `words` and an integer `k`, return: - the `k` most frequent distinct words, and - the `k` least frequent distinct words. Specify how you break ties (e.g., lexicographically, or any order). 2) **Stream version (online)**: Design a data structure that supports: - `ingest(word)`: process the next word in the stream - `topK(k)`: return the `k` most frequent distinct words seen so far - `bottomK(k)`: return the `k` least frequent distinct words seen so far Discuss time/space complexity and how you would implement these operations efficiently. 3) **Variant (discuss/design)**: Extend the stream design to support returning the **first `k`** and/or **last `k`** words that are currently **non-repeating** (i.e., words with frequency exactly 1) according to stream arrival order.