What is a doubly linked list and how is it different from a singly linked list?

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What is a doubly linked list and how is it different from a singly linked list?

A doubly linked list is a type of data structure in which each node contains two pointers, one pointing to the previous node and another pointing to the next node. This allows for traversal in both directions, forward and backward, within the list.

In contrast, a singly linked list only contains a single pointer that points to the next node, allowing traversal only in one direction, typically from the head to the tail of the list.

The main difference between a doubly linked list and a singly linked list lies in the additional pointer in the doubly linked list, which enables efficient traversal in both directions. This means that in a doubly linked list, we can easily access the previous node from any given node, whereas in a singly linked list, we would need to traverse the entire list from the beginning to reach the previous node.

Another difference is that a doubly linked list requires more memory compared to a singly linked list due to the extra pointer in each node. This additional memory overhead is a trade-off for the increased functionality and flexibility provided by the doubly linked list.

Additionally, the operations of insertion and deletion are more complex in a doubly linked list compared to a singly linked list. In a singly linked list, inserting or deleting a node requires updating only the pointers of the adjacent nodes. However, in a doubly linked list, these operations involve updating both the previous and next pointers of the affected nodes.

Overall, the choice between a singly linked list and a doubly linked list depends on the specific requirements of the application. If efficient traversal in both directions is necessary, a doubly linked list is preferred. However, if memory usage is a concern and traversal in only one direction is sufficient, a singly linked list may be more suitable.