Queues¶

A queue is a linear data structure that follows the FIFO (First In First Out) principle.

Characteristics¶

Elements are added from the rear and removed from the front
Used in scheduling, buffering, and task queues
Maintains insertion order for processing

Common Operations¶

Operation	Description	Time Complexity
`enqueue()`	Add an item to the rear of the queue	O(1)
`dequeue()`	Remove and return the front item	O(1)
`peek()`	View the front item without removing it	O(1)
`is_empty()`	Check if the queue is empty	O(1)

Visual Representation¶

       enqueue                dequeue
          ↓                      ↑
        ┌────┬────┬────┬────┬────┐
 Rear → │ 40 │ 30 │ 20 │ 10 │  5 │ ← Front
        └────┴────┴────┴────┴────┘

Implementation¶

Python's Queue class uses a list-based implementation with operations that maintain FIFO behavior.

# Example usage:
queue = Queue()
queue.enqueue(5)
queue.enqueue(10)
element = queue.dequeue()  # Returns 5

Applications¶

Task scheduling in operating systems
Print job queues
BFS (Breadth-First Search) algorithm
Request handling in web servers
Call center systems

Example Notebook¶

👉 See Queue Example Notebook