dqueues

Dqueues, also known as Deques or Double-ended Queues, are a data structure that generalizes a queue. Unlike a standard queue where elements can only be added or removed from one end (typically the rear and front, respectively), a deque allows for insertions and deletions at both ends. This means elements can be added to the front or rear, and removed from the front or rear.

Dqueues are a valuable tool in computer science for problems that require efficient access to both the beginning and end of a sequence. They can be implemented using various underlying structures, such as arrays or linked lists. An array-based implementation might use a circular buffer to manage the two ends, while a linked list implementation would involve a doubly linked list.

The operations typically supported by a deque include adding an element to the front (push_front), adding an element to the rear (push_back), removing an element from the front (pop_front), removing an element from the rear (pop_back), and accessing the element at the front (front) and rear (back) without removing them. Dqueues find applications in algorithms like breadth-first search where elements might need to be added to the front in certain scenarios, or in implementing certain types of buffers.