Compute reply-based engagement metrics

You work on a microblogging app (Twitter-like). Posts and replies are stored in the tables below. ### Tables #### `all_post` - `post_id` BIGINT **PK** - `post_author_id` BIGINT **FK → user.user_id** (author of this post/reply) - `post_creation_time` TIMESTAMP (assume UTC) - `post_type` VARCHAR (values: `'post'` for an original post, `'reply'` for a reply) - `post_content` TEXT - `post_parent_id` BIGINT NULL **FK → all_post.post_id** - For `post_type='reply'`, `post_parent_id` points to the post being replied to. - For `post_type='post'`, `post_parent_id` is NULL. #### `user` - `user_id` BIGINT **PK** - `age` INT - `country` VARCHAR (e.g., `'US'`, `'CA'`, ...) --- ## Task A For each original post (`post_type='post'`), consider replies to that post where the reply was created within **7 days** (inclusive) after the original post’s `post_creation_time`. Return the number of **distinct users** (`post_author_id` of the original post) who have **at least one** original post that received **≥ 2 replies** within that 7-day window. **Output:** - `num_users` ## Task B A user “receives a reply” if **any** of their original posts received a reply. Compute the percentage of users who received replies from **at least two distinct repliers** where both repliers are **US users** (`user.country='US'`). Repliers are the authors of the reply posts. **Output:** - `pct_users` (as a percentage from 0 to 100) **Clarification:** Use as denominator the number of distinct users who received **at least one** reply (i.e., exclude users who never received a reply).