Lesson 035
Queue Operations
Enqueue & Dequeue · FIFO
1:00How queues work — enqueue at the rear, dequeue from the front, FIFO ordering, edge-case guards, and why a circular buffer keeps both operations O(1).
By the end, you can
- Explain FIFO and distinguish a queue from a stack.
- Trace enqueue and dequeue operations on a concrete queue and predict the final state.
- Use peek(), isEmpty(), and isFull() correctly and state their time complexity.
- Identify underflow and overflow conditions and describe the appropriate guards.
- Explain why naive array dequeue is O(n) and how a circular buffer avoids that cost.
- Compute the next index after a wrap in a ring buffer using the expression `(i + 1) % SIZE`.
- Describe why front == rear is ambiguous in a circular buffer and how a count variable resolves it.
- List the correct sequence of steps for a circular-buffer enqueue and dequeue.
- Give three real-world systems that use queues and explain why FIFO is the right ordering for each.
Up next in Linear Data Structures
