Queue

A Queue is a fundamental data structure that follows the First-In-First-Out (FIFO) principle. It's similar to a real-world queue or line, where the first person to enter is the first to leave. Elements are added at the rear (enqueue) and removed from the front (dequeue) of the queue.

1. Basic Operations:
   • Enqueue: Add element to rear
   • Dequeue: Remove element from front
   • Front/Peek: View first element
   • IsEmpty: Check if queue is empty
2. Common Applications:
   • Task scheduling in operating systems
   • Print job management
   • Breadth-first search in graphs
   • Request handling in web servers
   • Buffer for data streams
3. Key Advantages:
   • Simple and intuitive implementation
   • Predictable element ordering
   • Efficient for FIFO operations

Complexity Analysis of Queue Operations

Queue operations have consistent time complexities:

• Time Complexity:
  • Enqueue (add): O(1)
  • Dequeue (remove): O(1)
  • Front/Peek: O(1)
  • IsEmpty: O(1)
  • Size: O(1)
• Space Complexity: O(n)
  • Space grows linearly with number of elements
  • Additional variables for front and rear tracking

Types of Queues:

• Simple Queue (Linear Queue)
• Circular Queue
• Priority Queue
• Double-ended Queue (Deque)
• Bounded Queue

Implementation Tips:

• Consider using circular implementation to avoid waste of space
• Handle queue overflow and underflow conditions
• Choose appropriate size for bounded queues
• Consider thread safety for concurrent applications
• Monitor performance in high-throughput scenarios