Extend Queue: Min-Size & Min-Sum Selector

Requirements

Start with a standard Queue type that offers enqueue and dequeue. Enhance the container that holds multiple queues so it can provide these two operations:

1. findQueueWithMinSize() — identify the queue, or its position, whose present number of items is lowest.
2. findQueueWithMinSum() — identify the queue, or its position, whose current total of stored values is lowest.

Be prepared to explain the supporting data structures you would keep and precisely how enqueue and dequeue change them.

Preparation

• Begin by outlining the public API. Then describe the auxiliary state behind each operation and specify what every enqueue and dequeue modifies. Evaluation emphasizes the design discussion as well as any code.
• Rehearse the contrast between querying by scan (inexpensive writes but costly reads) and maintaining running aggregates (more costly writes but fast reads). Interviewers commonly expect you to select one approach and defend that decision.