Arrays and Linked Lists: Implementation, Operations and Performance Analysis

Arrays and linked lists are pillars in the broad world of data structures, each providing a unique method for handling and organizing data within a program. Arrays are a straightforward yet effective design feature that offers contiguous memory storage and efficient access to elements via index-based retrieval. 

However, linked lists, a more complex structure, provide flexibility by using nodes connected in a chain to enable dynamic memory allocation and modification. This article will discuss arrays and linked lists, their complex implementations, explore the wide range of operations they provide, and evaluate their performance traits.

What is an Array?

A data structure with elements of a similar kind is called an array. The array is like a significant memory divided into small segments, each storing value and data. For example, if an array of 5 values exists, each block will have an integer type value. If the value differs in either of the blocks, it will show as an error.

Here is how an array is declared or written in programming:

Data_type name of the array[no of elements]

What is a Linked List?

A randomly stored collection of nodes is considered a linked list, where each node is made of links and data. The connection over here refers to the pointer holding the address of the next node, and data is the stored value in that specific node.

What distinguishes a Linked List from an Array?

The data structure that companies wish to use or follow depends highly on their specific requirements. Hence assuming that one is better than the other will be incorrect. It also depends on factors such as the data size, the operation performed on the data, etc. Here are some of how these two data structures differ from each other.

• Element Access

Accessing the elements will take constant time regardless of the array’s size. Companies can quickly locate the address of any part in an array if they know its base address since all objects in an array are stored adjacently. It would be best to calculate the value to find the address of any element in an array. As a result, the temporal complexity of accessing an array element is O(1).

Whereas, in the case of linked lists, the element storing is not done contiguously. In linked lists, there are many blocks, each with a specific node for themselves. Each node contains two fields: one holds the data, and the other holds the node’s address after it. 

Companies must first identify the head node, or the initial node, to locate any further nodes in the linked list. In the worst-case scenario, they would have to visit all the nodes to discover the last node in the list if they needed to find the second node. The typical element access situation has an O(n) complexity.

Performance Analysis – Array will be a better choice to access elements.

• Element Insertion

An element can be inserted in three ways:

  • In the Beginning

In the case of an array, to insert an element in the starting, you will have to shift the details on the right side to create space. As a result, the length of the list will directly affect how time-consuming the operation is. The array’s size, n, would determine the time complexity, O(n).

Similarly, in the case of linked lists, you must create a new node, and the first node’s address is added to it for inserting an element in the beginning. Therefore, the new node is now the starting node. So, the temporal complexity does not follow the length of the list. Constant time complexity, or O(1), would apply.

  • In the End

If the array isn’t complete, the new element can be added immediately using the index. The time complexity in this scenario would be constant, or O(1). If the array is already full, replicate it into another array before adding a new entry. The temporal complexity in this scenario would be O(n).

On the other hand, you must traverse the entire linked list to insert an entry at the end of it. The temporal complexity would be O(n) if the linked list had n elements.

  • In the Middle

In the case of an array, you will have to move the n/2 items to the right to insert the element at the ith position of the array. As a result, the time complexity is inversely correlated with the number of components. In most cases, the temporal complexity would be O(n).

In the case of a linked list, you will have to traverse to the location where the new element has to be inserted. Even if no moving is required, you must move to position n/2. The time required is proportional to the n number of elements, and the typical situation would have an O(n) time complexity.

Performance Analysis – It is easy to use an array versus a linked list during programming as the latter is prone to more errors.

• Memory

An array has a fixed size since the elements are stored in one contiguous memory block. For example, the remaining space will be free if your array is 7 bytes and only has four elements. So, memory space will be 7*4 = 28 bytes.

In the case of linked lists, there is nothing like unused or free memory. Instead, it is used by the pointer variables. If the data is of the integer type, then one node uses 8 bytes of memory, divided into 4 bytes for the data and 4 bytes for the pointer variable. A linked list with four elements takes up 32 in memory (8*4 = 32 bytes).

Performance Analysis – Using linked lists is better if your data size is big.


In conclusion, arrays work better when quick element access and a small memory footprint matter. When efficient insertions, deletions, and dynamic size changes are priorities, particularly at the beginning or both ends, linked lists are preferred.

Both Array and linked lists are excellent data structures and come attached with their share of pros and cons. Depending on different factors, the companies should decide which one will be better for their business.



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