Find Top K Users by Chat Logs

Given a set of chat log records, you need to find the top k users who send the most messages. Implement a function find_top_k_users(logs: List[str], k: int) -> List[str>, where logs is a list of strings representing user messages (e.g., "user_id message"), and k is the number of top users to query. Return the user_ids of the top k users. Assume the number of users and log length do not exceed $10^5$. Provide test cases. Example Input 10 a 1 b 1 a 2 c 1 a 1 b 2 d 4 a 1 d 3 b 1 3