Stack/queue simulation and algorithm choice

≈ 45 min

Stack/queue simulation and algorithm choice

Data-structure questions often hide the required order inside ordinary language. “Undo the latest edit” suggests a stack. “Serve requests in arrival order” suggests a queue. “Handle urgent cases first” suggests a priority rule that must be defined and audited. Before simulating, draw the structure with a labelled front/back or top so that additions and removals cannot silently swap places.

Simulation is an evidence tool. List each operation, update the structure, then record the returned item. A queue can be implemented with a circular array or linked nodes, but the algorithmic contract remains first-in, first-out. If the implementation can overflow or underflow, the method must report or prevent that invalid operation.

Worked reasoning. A help desk enqueues A, B and C; it dequeues once; then enqueues D; then dequeues twice. The returned sequence is A, B, C and the remaining queue is D. The key is to update the front after each dequeue, not simply remove the last written label.

Exam lens. For a simulation question, write the state after every operation. A correct final answer with no trace is difficult to verify and easy to reverse.

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Which statement is the most defensible principle for Stack/queue simulation and algorithm choice?

Simulate each operation in order and choose the structure from the service rule, not from its name.

Treat an implementation detail as more important than the stated rule.

Assume one successful run proves the system is correct in every case.

Avoid recording assumptions, limits or failure conditions.

Enter the key term for Stack/queue simulation and algorithm choice. What queue operation removes the item that has waited at the front?

An online support system must answer the oldest waiting question first. Which operation removes the next question?

Dequeue removes the front item of the queue, which is the oldest waiting question.

Use a larger class or broader permission without stating a rule.

Trust the first output and skip a boundary or failure check.

Hide the decision so affected people cannot inspect it.

Name the concise safeguard or principle that completes this lesson’s scenario: An online support system must answer the oldest waiting question first. Which operation removes the next question?