Analyze time complexity and threading trade-offs

Answer the conceptual questions below.

1) Worst-case time complexity

For each operation, give the worst-case time complexity (Big-O) and briefly explain your answer.

1. Delete an element by value from a sorted array.
2. Determine whether a given key exists in a hash table.
3. Delete the minimum element from a min-heap.
4. Return the value of the i-th element in a sorted array, assuming a 0-based index.

2) Multithreading vs single-threading

Is multithreading always faster than single-threading? Explain why or why not, and provide at least one concrete example where multithreading is slower.

Overview: This question assesses understanding of worst-case time complexity for common data structure operations and the performance trade-offs between multithreading and single-threading, within the Software Engineering Fundamentals domain.