How are linked lists different from arrays in data structure?

Linked lists and arrays are different in their structure, memory allocation, and operations efficiency.

In a nutshell, an array is a static data structure, while a linked list is a dynamic data structure. This fundamental difference in their nature leads to several other distinctions. An array is a collection of elements of similar data types stored in contiguous memory locations. On the other hand, a linked list is a collection of elements, known as nodes, where each node is linked to the next one through a pointer.

Memory allocation in arrays is done at compile time, making them static in nature. This means that the size of an array is fixed and cannot be changed once it is declared. This can lead to inefficient use of memory if the array is not fully utilised. In contrast, memory allocation in linked lists is done at runtime, making them dynamic. This allows for efficient use of memory as the size of the linked list can be altered during the execution of the program.

The structure of an array is simple and straightforward. It consists of a collection of elements that are accessed by their index. This allows for quick access to elements as the index directly maps to the memory location of the element. However, this is not the case with linked lists. In a linked list, elements are scattered in memory and are linked together using pointers. This means that to access an element, you have to traverse the entire list from the start to the desired element, making access slower than in arrays.

In terms of operations efficiency, insertion and deletion of elements in an array is time-consuming as the position of existing elements needs to be adjusted each time. However, in a linked list, these operations are faster and easier as it only involves the reassignment of pointers.

In conclusion, while arrays and linked lists are both fundamental data structures used in computer science, they have distinct differences in their structure, memory allocation, and operations efficiency. Understanding these differences is crucial in choosing the right data structure for a specific task or problem.