Optiver Software Engineer System Design Questions

Background: In trading systems, efficient management of orders and trades is crucial for optimizing performance. A circular buffer queue can help manage orders in a first-in-first-out (FIFO) manner while utilizing fixed memory efficiently.Requirements:
1. Implement a circular buffer with a specified capacity.
2. Provide methods to enqueue and dequeue items from the queue.
3. Ensure that the queue supports checking if it is empty or full.
4. Methods must handle concurrent access safely.
5. Provide a method to clear the queue.Class API:

• def __init__(self, capacity: int) -> None: Initializes the circular buffer queue with a given capacity.


• def enqueue(self, item: Any) -> None: Adds an item to the queue. Raises an error if the queue is full.


• def dequeue(self) -> Any: Removes and returns the item at the front of the queue. Raises an error if the queue is empty.


• def is_empty(self) -> bool: Returns True if the queue is empty, otherwise False.


• def is_full(self) -> bool: Returns True if the queue is full, otherwise False.


• def clear(self) -> None: Clears all items from the queue.

Example 1:
Input: CircularBufferQueue(3) followed by enqueue(1), enqueue(2), enqueue(3), dequeue() → Output: 1 → Explanation: The queue initially contains [1,2,3]. After dequeuing, the first item is removed.Example 2:
Input: CircularBufferQueue(2) followed by enqueue(10), enqueue(20), enqueue(30) → Output: Error → Explanation: The third enqueue operation fails because the queue is full.Constraints:

• capacity (1 <= capacity <= 10000)


• Number of enqueue and dequeue operations should not exceed 10000.


• Proper handling of concurrent accesses should be provided.

Background: At Optiver, software systems must efficiently handle real-time data processing and manage state changes. A circular buffer can provide efficient storage for incoming data streams, reducing overhead needed for dynamic resizing.
Requirements:
1. The buffer must be able to store a fixed maximum number of elements.
2. It should provide methods to add an element to the buffer and retrieve the oldest element.
3. Implement methods to check if the buffer is empty or full.
4. Ensure thread safety when accessing the buffer.
Class API:

• def __init__(self, capacity: int) -> None: Initializes the circular buffer with a given capacity.


• def enqueue(self, value: Any) -> None: Adds an element to the buffer, raises an exception if the buffer is full.


• def dequeue(self) -> Any: Removes and returns the oldest element, raises an exception if the buffer is empty.


• def is_full(self) -> bool: Returns True if the buffer is full, otherwise False.


• def is_empty(self) -> bool: Returns True if the buffer is empty, otherwise False.

Example 1:
Input: cb = CircularBuffer(3); cb.enqueue(1); cb.enqueue(2); cb.enqueue(3) → Output: None, Explanation: The buffer contains [1, 2, 3].
Example 2:
Input: cb.dequeue() → Output: 1, Explanation: Removes 1, buffer now contains [2, 3].
Constraints:

• Maximum capacity of the buffer: 1 <= capacity <= 10^6.


• Buffer operations must handle concurrent access safely.