Why exactly do we need a “Circular Linked List” (singly or doubly) data structure?

Question

Why exactly do we need a \"Circular Linked List\" (singly or doubly) data structure?

What problem does it solve that is evident with simple Linked Lists (singly or doubl

Answer 1

A circular list is simpler than a normal doubly-linked list. Append is just prepend and shift forward once, Pop back is just shift back once and pop front. By tying the two ends together, you get a double-ended list for the cost of just implementing the operations of a one-ended list.

Answer 2

Something i found from google.

A singly linked circular list is a linked list where the last node in thelist points to the first node in the list. A circular list does not contain NULL pointers.

A good example of an application where circular linked list should be used is a timesharing problem solved by the operating system.

In a timesharing environment, the operating system must maintain a list of present users and must alternately allow each user to use a small slice of CPU time, one user at a time. The operating system will pick a user, let him/her use a small amount of CPU time and then move on to the next user, etc.

For this application, there should be no NULL pointers unless there is absolutely no one requesting CPU time.

Answer 3

A good example of an application where circular linked list should be used is a timesharing problem solved by the operating system.

Answer 4

Two reasons to use them:

1) Some problem domains are inherently circular.

For example, the squares on a Monopoly board can be represented in a circularly linked list, to map to their inherent structure.

2) Some solutions can be mapped to a circularly linked list for efficiency.

For example, a jitter buffer is a type of buffer that takes numbered packets from a network and places them in order, so that (for example) a video or audio player can play them in order. Packets that are too slow (laggy) are discarded.

This can be represented in a circular buffer, without needing to constantly allocate and deallocate memory, as slots can be re-used once they have been played.

It could be implemented with a linked-list, but there would be constant additions and deletions to the list, rather than replacement to the constants (which are cheaper).

Answer 5

A circular linked list can be effectively used to create a queue (FIFO) or a deque (efficient insert and remove from front and back). See http://en.wikipedia.org/wiki/Linked_list#Circularly-linked_vs._linearly-linked

Answer 6

Circular linked lists are widely used in applications where tasks are to be repeated or in time sharing applications. Circular queue can keep a track of tasks which have been performed and which has to be performed,once the specific task is done it jumps to next one and when whole set of task is conpleted it again jumps to first task to complete the remaining job. In practical use : when you open multiple applications on your system the memory of those applications are saved in a circular fashion, you can observe this if u continuously press win+tab/alt+tab for switching applications. Also in multiplayer board games ,each player are assigned to node in the linked list and the rotation is performed