LeetCode 3497: Analyze Subscription Conversion Solution

Explanation:

To solve this problem, we need to perform the following steps:

1. Identify users who converted from free trial to paid subscription.
2. Calculate the average daily activity duration during the free trial period for each user.
3. Calculate the average daily activity duration during the paid subscription period for each user.
4. Return the result table ordered by user_id in ascending order.

Algorithm:

1. Create a temporary table to store the free trial activities and another temporary table to store the paid subscription activities.
2. Join the UserActivity table with itself on user_id and activity_date to get the free trial end date and the paid subscription start date for each user.
3. Calculate the average daily activity duration during the free trial period for each user and store it in the free trial temporary table.
4. Calculate the average daily activity duration during the paid subscription period for each user and store it in the paid subscription temporary table.
5. Join the free trial and paid subscription temporary tables on user_id to get the final result table.
6. Filter out users who did not convert from free trial to paid subscription.
7. Return the result table ordered by user_id in ascending order.

Time Complexity: O(n log n) where n is the number of rows in the UserActivity table. Space Complexity: O(n) for the temporary tables.

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