What's the difference between array and linked list in data representation?

Array and linked list differ in their structure, memory allocation, and operations efficiency.

An array is a data structure that stores elements of the same type in a contiguous block of memory. It is a static data structure, meaning its size is fixed at the time of creation. Each element in an array is identified by an index, which represents its position in the array. This allows for quick access to elements, making arrays efficient for tasks that require frequent, direct access to individual elements. However, arrays are less efficient when it comes to operations like insertion and deletion, as these operations require shifting of elements.

On the other hand, a linked list is a dynamic data structure, meaning its size can change during the execution of a program. It consists of nodes, where each node contains a data element and a reference (link) to the next node in the sequence. This allows for efficient insertions and deletions, as these operations only require changing the links that point to the affected nodes. However, linked lists do not provide direct access to individual elements. To access an element, one must start at the first node and follow the links to the desired node. This makes linked lists less efficient for tasks that require frequent, direct access to individual elements.

In terms of memory allocation, arrays require a contiguous block of memory, which can be a limitation if large arrays are needed and memory is fragmented. Linked lists, however, do not require contiguous memory, as each node can be stored anywhere in memory. This makes linked lists more flexible in terms of memory usage.

In summary, the choice between using an array or a linked list depends on the specific requirements of the task at hand. If frequent, direct access to individual elements is needed, an array would be the better choice. If the task involves frequent insertions and deletions, a linked list would be more efficient.