Answer the following conceptual questions. ## 1) Worst-case time complexity State the **worst-case time complexity (Big-O)** for each operation and briefly justify. 1. Remove an element (by value) from a **sorted array**. 2. Check whether a given **key exists in a hash table**. 3. Remove the minimum element from a **min-heap**. 4. Find the **i-th element** in a **sorted array** (assume 0-based index) and return its value. ## 2) Multithreading vs single-threading Is multithreading **always** faster than single-threading? Explain why or why not, and give at least one concrete example where multithreading is slower.