Prerequisite – Circular Singly Linked List
We have discussed basics and how to implement circular queue using array in set 1.
Circular Queue | Set 1 (Introduction and Array Implementation)
In this post another method of circular queue implementation is discussed, using Circular Singly Linked List.
Operations on Circular Queue:
- Front:Get the front item from queue.
- Rear: Get the last item from queue.
- enQueue(value) This function is used to insert an element into the circular queue. In a circular queue, the new element is always inserted at Rear position.
- Create a new node dynamically and insert value into it.
- Check if front==NULL, if it is true then front = rear = (newly created node)
- If it is false then rear=(newly created node) and rear node always contains the address of the front node.
- deQueue() This function is used to delete an element from the circular queue. In a queue, the element is always deleted from front position.
- Check whether queue is empty or not means front == NULL.
- If it is empty then display Queue is empty. If queue is not empty then step 3
- Check if (front==rear) if it is true then set front = rear = NULL else move the front forward in queue, update address of front in rear node and return the element.
Below is the implementation of above approach:
Elements in Circular Queue are: 14 22 6 Deleted value = 14 Deleted value = 22 Elements in Circular Queue are: 6 Elements in Circular Queue are: 6 9 20
Time Complexity: Time complexity of enQueue(), deQueue() operation is O(1) as there is no loop in any of the operation.
Note: In case of linked list implementation, a queue can be easily implemented without being circular. However, in the case of array implementation, we need a circular queue to save space.
This article is contributed by Akash Gupta. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
- Circular Queue | Set 1 (Introduction and Array Implementation)
- Circular Linked List | Set 2 (Traversal)
- Reverse a circular linked list
- Sum of the nodes of a Circular Linked List
- Deletion from a Circular Linked List
- Queue - Linked List Implementation
- Convert singly linked list into circular linked list
- Deletion at different positions in a Circular Linked List
- Delete all the even nodes of a Circular Linked List
- Reverse a doubly circular linked list
- Delete every Kth node from circular linked list
- Doubly Circular Linked List | Set 2 (Deletion)
- Count nodes in Circular linked list
- Circular Linked List | Set 1 (Introduction and Applications)
- Split a Circular Linked List into two halves