# Data Structures: Question Set – 07

#### What is the time complexity of enqueue and dequeue operations in a queue?

The time complexity of enqueue and dequeue operations in a queue is O(1), which means that these operations can be performed in constant time.

#### What is the front element of a queue?

The front element of a queue is the element that has been in the queue for the longest time.

#### How do you check if a queue is empty?

You can check if a queue is empty by checking if the front element of the queue is null or by keeping track of the number of elements in the queue.

#### What is a priority queue?

A priority queue is a variant of a queue where each element is assigned a priority and the element with the highest priority is always at the front of the queue. Elements with the same priority are ordered based on the order in which they were added to the queue.

#### What is a circular queue?

A queue can be classified as circular if the very last item in the queue contains a pointer that leads all the way back to the very first item in the queue. This makes it possible to make effective use of the available space, and it may be achieved by wrapping around to the beginning of the array using modular arithmetic applied to an array.

#### What is a double-ended queue or deque?

A deque is a special kind of queue that allows items to be inserted into or deleted from the collection from either the front or the back. This enables a greater degree of freedom in the manner in which the data is organised and can be realised through the utilisation of a doubly linked list.

#### What is meant by the term “blocking queue”?

A form of queue known as a blocking queue is one in which the enqueue and dequeue procedures both block, or wait, if the queue in question is either empty or full, respectively. When data needs to be synchronised between different threads in an application that uses many threads, this can be helpful.

#### How is a circular queue implemented?

Either an array or a linked list data structure can be used to accomplish the functionality of a circular queue. When the queue is implemented using an array, there are two pointers—referred to as the front and the rear—that are used to maintain track of the first and last items in the queue.

#### What are the benefits of employing a circular queue as opposed to a standard queue?

Because it recycles the spaces that would otherwise be left empty, a circular queue is more effective than a traditional queue in terms of utilisation of resources. It also makes it possible to remove pieces efficiently from the front of the vehicle and add elements to the back of the vehicle.

#### What is the time complexity of the primary operations of a circular queue?

The implementation of a circular queue can have a significant impact on the amount of time required for its principal functions. The temporal complexity of enqueue and dequeue operations is, on average, O(1) when an array is used for the implementation. Enqueue and dequeue operations in a linked list implementation have a time complexity of O(1) on average, which is the same as the difficulty of the operation.