ABC Technologies

1. Explain what a circuit board is.

2. Tell me about 5 array functions in PHP.

3. Priority Queue Implementation Implement a priority queue that supports the following operations: insert, remove, and peek. The priority queue should allow for both integer and string priorities. Provide the code along with a brief explanation of the underlying data structure used.

4. How do you implement multi-threading?

5. Given two tables, join them based on a unique ID.