# What Is Insertion and Deletion in Data Structure?

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Scott Campbell

In the world of data structures, two fundamental operations play a crucial role in manipulating and modifying data: Insertion and Deletion. These operations allow us to add new elements or remove existing ones from a data structure. Let’s delve into each operation to understand their significance and usage.

## Insertion:

When we talk about insertion, we refer to the process of adding an element to a specific position within a data structure. This operation is essential for maintaining the integrity and functionality of various data structures.

### Insertion in Arrays:

Arrays are one of the simplest yet most widely used data structures. Inserting an element into an array requires shifting all the subsequent elements to the right after the desired position. Let’s consider an example:

Suppose we have an array [1, 2, 4, 5], and we want to insert the element 3 at index 2. The insertion process involves shifting all elements from index 2 onwards by one position to make room for the new element:

Before Insertion: [1, 2, 4, 5]
After Insertion: [1, 2, 3, 4, 5]

As you can see, inserting an element in an array can be a time-consuming operation since it requires shifting multiple elements.

Unlike arrays, linked lists offer more flexibility when it comes to insertion. In a linked list, each element (node) contains a reference or pointer to the next node. To insert an element into a linked list, we need to modify these pointers accordingly.

Let’s consider another example:

Suppose we have a linked list with three nodes: A -> B -> C. We want to insert a new node ‘D’ between nodes B and C. The insertion process involves changing the pointer of node B to point to the newly inserted node D, which, in turn, points to node C:

Before Insertion: A -> B -> C
After Insertion: A -> B -> D -> C

As you can see, inserting an element in a linked list is relatively efficient compared to an array since it does not require shifting multiple elements.

## Deletion:

While insertion adds new elements to a data structure, deletion removes existing elements. Similar to insertion, deletion plays a vital role in maintaining the integrity and functionality of data structures.

### Deletion in Arrays:

Deleting an element from an array involves shifting all subsequent elements towards the left after removing the desired element. Let’s consider an example:

Suppose we have an array [1, 2, 3, 4, 5], and we want to delete the element at index 2. The deletion process involves shifting all elements from index 3 onwards by one position to fill the gap created by removing the element:

Before Deletion: [1, 2, 3, 4, 5]
After Deletion: [1, 2, 4, 5]

As you can see, deleting an element from an array can also be time-consuming since it requires shifting multiple elements.

In linked lists, deletion is relatively straightforward compared to arrays. To delete a node from a linked list, we need to modify the pointers of adjacent nodes accordingly.

Suppose we have a linked list with four nodes: A -> B -> C -> D. We want to delete node C from the list. The deletion process involves changing the pointer of node B to point directly to node D:

Before Deletion: A -> B -> C -> D
After Deletion: A -> B -> D

As you can see, deleting an element from a linked list is efficient since it only involves modifying a few pointers.

## Conclusion:

Insertion and deletion are fundamental operations in data structures that allow us to manipulate and modify data. While arrays require shifting elements for insertion and deletion, linked lists offer more flexibility by modifying pointers.

Understanding these operations is crucial for effectively utilizing and implementing various data structures. By mastering insertion and deletion, you’ll have the power to efficiently manage data in any scenario.