Explain the role of a linked list in implementing other data structures.

A linked list is used in implementing other data structures like stacks, queues, and hash tables.

A linked list is a dynamic data structure that can grow or shrink during the execution of a program, making it ideal for implementing other data structures. It consists of nodes, where each node contains a data field and a reference (link) to the next node in the sequence. This structure allows efficient insertions and deletions at any position in the sequence, which is a crucial feature for many data structures.

For instance, stacks and queues are often implemented using linked lists. A stack is a data structure that follows the Last-In-First-Out (LIFO) principle, meaning the last element added is the first one to be removed. A linked list can easily implement this by adding and removing elements at the head of the list. Similarly, a queue follows the First-In-First-Out (FIFO) principle, where the first element added is the first one to be removed. This can be implemented using a linked list by adding elements at the tail and removing them from the head.

Hash tables, another common data structure, can also be implemented using linked lists. A hash table uses a hash function to compute an index into an array of buckets or slots, from which the desired value can be found. Collisions occur when the hash function returns the same index for multiple keys. One way to handle collisions is by using linked lists. Each bucket in the hash table will have a linked list. When a collision occurs, the new key-value pair is added to the end of the linked list in the corresponding bucket.

In addition, linked lists are used in the implementation of graphs. In an adjacency list representation of a graph, each vertex has a linked list of the vertices it is connected to. This allows for efficient traversal and manipulation of the graph.

In conclusion, the linked list's dynamic and flexible nature makes it a fundamental tool in the implementation of various data structures. Its ability to efficiently handle insertions and deletions at any position is a key feature that is utilised in stacks, queues, hash tables, and graphs.