What is the difference between a singly linked list and a doubly linked list?

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What is the difference between a singly linked list and a doubly linked list?

A singly linked list is a type of data structure where each node contains a data element and a reference (or link) to the next node in the list. It can only be traversed in one direction, starting from the head (or first) node and moving towards the tail (or last) node. The last node in the list points to null, indicating the end of the list.

On the other hand, a doubly linked list is a data structure where each node contains a data element and two references (or links) - one to the previous node and one to the next node in the list. This allows for traversal in both directions, from the head to the tail and vice versa. The first node's previous reference and the last node's next reference point to null, indicating the start and end of the list, respectively.

The main difference between a singly linked list and a doubly linked list is the presence of the previous reference in the doubly linked list. This additional reference allows for more flexibility in traversing and manipulating the list, but it also requires more memory to store the extra reference in each node.

In terms of operations, both types of linked lists support insertion and deletion of nodes. However, in a singly linked list, deleting a node requires updating the next reference of the previous node to skip the deleted node, while in a doubly linked list, deleting a node requires updating both the next and previous references of the adjacent nodes to maintain the integrity of the list.

Overall, the choice between a singly linked list and a doubly linked list depends on the specific requirements of the application. If bidirectional traversal and manipulation are necessary, a doubly linked list is preferred. However, if memory efficiency is a concern and bidirectional traversal is not required, a singly linked list may be more suitable.