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

Algorithm Design Questions Medium



49 Short 51 Medium 39 Long Answer Questions Question Index

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

A linked list is a data structure where each element, called a node, contains a value and a reference to the next node in the list. It is a linear data structure that allows for efficient insertion and deletion at any position, but accessing elements in the middle of the list requires traversing from the beginning.

On the other hand, a doubly linked list is a variation of a linked list where each node contains an additional reference to the previous node in the list. This allows for bidirectional traversal, meaning we can traverse both forward and backward in the list. Each node in a doubly linked list has two pointers, one pointing to the previous node and another pointing to the next node.

The main difference between a linked list and a doubly linked list is the presence of the previous node reference in a doubly linked list. This additional reference enables efficient backward traversal, which is not possible in a regular linked list. However, this comes at the cost of increased memory usage due to the extra pointer in each node.

In terms of operations, both linked lists and doubly linked lists support insertion and deletion at any position. However, in a doubly linked list, these operations require updating both the next and previous pointers of the affected nodes, while in a linked list, only the next pointer needs to be updated.

Overall, the choice between a linked list and a doubly linked list depends on the specific requirements of the problem at hand. If bidirectional traversal is necessary or frequently performed, a doubly linked list may be more suitable. Otherwise, a regular linked list can be used to achieve efficient insertion and deletion operations.