Notion Frontend Engineer Coding Questions

Notion allows multiple users to edit a page simultaneously. In order to keep track of the changes made by users, you are tasked with implementing a system that records revisions based on timestamps. Use a heap to maintain the last n changes made on the page with the given timestamps.
### Problem Statement:
You are given an array of revision records where each record consists of a string user, a string change, and an integer timestamp. Implement a ChangeLog class, which maintains the n most recent changes in their chronological order. The class should support the following methods:
- addChange(user: str, change: str, timestamp: int): Adds a new change to the log.
- getRecent(n: int) -> List[str]: Returns a list of the last n changes in chronological order of their timestamps.
### Example 1:
Input:
python
log = ChangeLog(3)
log.addChange("Alice", "Added a new section", 1)
log.addChange("Bob", "Fixed a typo", 2)
log.addChange("Alice", "Updated the header", 3)
log.getRecent(2)

Output: ['Fixed a typo', 'Updated the header']
### Example 2:
Input:
python
log.addChange("Charlie", "Removed a line", 4)
log.getRecent(3)

Output: ['Added a new section', 'Fixed a typo', 'Updated the header']
### Constraints:
- 1 <= n <= 1000
- 1 <= timestamp <= 10^6

Notion's collaborative interface demands efficient rendering of content for real-time updates and smooth interactions. Implement a function to calculate the maximum number of unique words that can be displayed within a sliding window of a given size.
### Problem Statement:
You are given a string text which represents a Notion page's content, and an integer k representing the size of the sliding window. Your task is to find the maximum number of unique words present in any contiguous substring of text with length k. You need to return this maximum count.
### Example 1:
Input: text = "This is a sample Notion page, Notion pages are great!", k = 20
Output: 8
Explanation: "a sample Notion page, Notion pages are" contains 8 unique words.
### Example 2:
Input: text = "Test Test Test!", k = 10
Output: 2
Explanation: The unique words in the substring of length 10 are "Test Test" which contains 2 unique words.
### Constraints:
- 1 <= k <= text.length
- text.length <= 10^5