A Queue is a fundamental linear data structure that operates on the First In, First Out (FIFO) principle, making it an essential tool for managing ordered processes in computer science. This versatile data structure is widely used in various applications, from task scheduling in operating systems to handling requests in web servers.
Core Characteristics
- Follows the FIFO principle - First element added is the first to be removed
- Maintains two points of access (front and rear)
- Provides constant-time operations for basic functions
- Ideal for managing ordered processes and task scheduling
Key Operations
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Enqueue() This operation adds a new element to the rear of the queue. The newly added element becomes the new rear, while maintaining the order of previously added elements. This operation is crucial for building the queue and maintaining its FIFO property. Complexity: O(1) - Constant time operation
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Dequeue() This operation removes and returns the front element of the queue. Following the FIFO principle, it always removes the oldest element in the queue. This operation is essential for processing elements in the order they were added. Complexity: O(1) - Constant time operation
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Front() This operation inspects the front element without removing it. It's particularly useful for checking the next element to be processed without modifying the queue's contents, making it ideal for queue state validation and conditional operations. Complexity: O(1) - Constant time operation
Common Applications
- Task scheduling in operating systems
- Request handling in web servers
- Breadth-first search (BFS) in graph algorithms
- Print job management
- Message queuing systems