Stack/QueueStack & Queue

Queue (FIFO)

A first-in, first-out collection: elements enter at the back and leave from the front.

Commands — Comma separated: enqueue N, dequeue, peek

1/12A queue is first-in, first-out: elements enter at the back and leave from the front, so the order of arrival is preserved.

Just enqueuedFrontBeing dequeued

1enqueue(x): items.append(x)      # at the back
2dequeue(): return items.pop_front()  # from the front
3peek(): return items[front]

Variables

size0

Complexity

access O(n)

search O(n)

insert O(1)

delete O(1)

Speed