Lecture on Queues

Introduction to Queues

• Queues are an elementary data structure.
• Represent a dynamic set of data.
• Operations include insertion and deletion.
• Follows the FIFO (First In First Out) principle.
  • Insert Method: Called enqueue.
  • Delete Method: Called dequeue, takes no arguments.

Example of a Queue

• Representation of a queue involves marking the front and the back.
• Implemented in Python using collections.deque (a doubly linked list).
  • Allows enqueue and dequeue in constant time.
• Elements inserted at the back, removed from the front.
  • Start with an empty queue.
  • Enqueue element 1 (added at the back, hence first in line).
  • Enqueue elements 2 and 3 (added at the back behind 1).
  • Dequeue removes element 1 (the first element added).

Python Implementation

• Use collections.deque as a queue.
• Define enqueue and dequeue methods.
  • Enqueue: Append the element to the end.
  • Dequeue: Use pop left to remove the front element.
  • Operations in constant time due to doubly linked list structure.

Practical Uses of Queues

• Extensively used in operating systems for CPU and disk scheduling.
• Example: Adding a song to a queue in Spotify.
• Implement breadth-first search in various algorithms.

Conclusion

• Queues are fundamental in computer science with numerous applications.
• Further learning encouraged through other videos.
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