The Art of Queuing: Applications of Queues in Data Structures

This article introduces the queue data structure. In daily life, queuing (such as getting meals in a cafeteria) embodies the "first-come, first-served" principle, which is the prototype of a queue. A queue is a data structure that follows the "First-In-First-Out" (FIFO) principle. Its core operations include enqueue (adding an element to the tail of the queue) and dequeue (removing the earliest added element from the front of the queue). Additionally, operations like viewing the front element and checking if the queue is empty are also supported. Queues differ from stacks (which follow the "Last-In-First-Out" (LIFO) principle); the former adheres to "first-come, first-served," while the latter reflects "last-come, first-served." Queues have wide applications: In computer task scheduling, systems process multiple tasks in a queue (e.g., programs opened earlier receive CPU time first); the BFS (Breadth-First Search) algorithm uses a queue to expand nodes level by level, enabling shortest path searches in mazes; during e-commerce promotions, queues buffer user requests to prevent system overload; in multi-threading, producers add data to a queue, and consumers process it in order, facilitating asynchronous collaboration. Learning queues helps solve problems such as processing data in sequence and avoiding resource conflicts, making it a fundamental tool in programming and algorithms. Understanding the "First-In-First-Out" principle contributes to efficiently solving practical problems.