Implement CSAT tracking and call timing

You were asked to solve two coding problems. ### Problem 1: Implement a rolling CSAT tracker Implement a class `CSATTracker` for customer-satisfaction scores. Each recorded score: - belongs to a unique `conversation_id` - is an integer from 1 to 5 - has an integer timestamp The tracker uses a rolling window of size `window_size`. A record is active at time `t` if `record_timestamp >= t - window_size`. Implement: 1. `__init__(window_size: int)` 2. `record(conversation_id: str, score: int, timestamp: int) -> None` - Insert the score. - After insertion, evict any records that are no longer in the active window relative to `timestamp`. 3. `get_average(current_time: int) -> Optional[float]` - Before computing the result, evict any records older than the active window relative to `current_time`. - Return the average active score rounded to 2 decimal places. - Return `None` if there are no active records. 4. `update(conversation_id: str, score: int) -> None` - Update the score for an existing active conversation. - If that conversation has already been evicted, do nothing. - Updating a score must not change its timestamp or its position in eviction order. Assumptions: - `conversation_id` values passed to `record` are unique. - Calls to `record` and `get_average` occur in non-decreasing timestamp order. - The goal is to support these operations efficiently without scanning all stored records on every call. ### Problem 2: Compute exclusive runtime from nested call logs A single-threaded CPU runs `n` functions identified by IDs `0` to `n - 1`. You are given a list of execution logs sorted by timestamp. Each log has the form `function_id:start:timestamp` or `function_id:end:timestamp`. Rules: - A function may call another function, which pauses the currently running one. - Functions may be nested multiple levels deep. - An `end` event at time `t` means the function finishes at the end of time unit `t`, so that unit counts toward the function's runtime. Return an array `answer` where `answer[i]` is the exclusive execution time of function `i`, excluding time spent in any child calls. You may assume the logs are valid and represent a properly nested execution trace.