DSA · Theory

Priority Queue

Theory

25/810

If you can teach Priority Queue using print jobs, you know it. If you only know the heading, you don’t.

Do Priority Queue once by hand. enqueue / dequeue FIFO. Change one input. Say the new result out loud.

Without Priority Queue, a lab printer gets messy and print jobs is hard to trust.

Priya ships Priority Queue in a lab printer. That is the use case worth saying.

Priority Queue trap — confusing front and rear. Priya loses marks for that every viva.

Place Priority Queue next to nearby DSA work — enqueue / dequeue FIFO is the link.

One breath for Priority Queue, then print jobs, then confusing front and rear. Sit down.

Diagram

  front → [A][B][C] ← rear
  out ↑         ↑ in
       FIFO

Exam tip

For Priority Queue: definition + a lab printer + one failure.

from collections import deque

q = deque()
q.append(10)      # enqueue
q.append(20)
print(q.popleft())  # 10
print(list(q))

Priority Queue — queue is FIFO. deque.popleft() is O(1).