Find top-k lottery winners by spending

You are building a lottery system where each user’s chance of winning is **linearly proportional** to how much they spent (e.g., user with spend `s` has weight `s`). Given: - An array of participants, each with a unique `user_id` and a non-negative integer `spend`. - An integer `k`. Task: - Return the **`k` users with the highest winning probability**, i.e., the `k` users with the largest `spend` values. Clarifications to handle: - If `k` is greater than the number of users, return all users. - Define how to break ties (e.g., by `user_id` ascending) and keep it consistent. - Discuss time and space complexity of your approach. Example: - Input: `[(A, 10), (B, 5), (C, 10), (D, 1)], k=2` - Output (one valid): `[A, C]` (tie broken deterministically)