# What Is Merge Sort in Data Structure?

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Heather Bennett

Merge Sort is a popular sorting algorithm in the field of data structure. It is based on the divide-and-conquer technique, which involves breaking down a problem into smaller subproblems, solving them independently, and then combining the results to obtain the final solution.

## How does Merge Sort work?

The Merge Sort algorithm follows three main steps:

1. Divide: The unsorted list is divided into smaller sublists until each sublist contains only one element. This is done recursively, splitting the list in half until we reach the base case.
2. Conquer: The sublists are sorted individually by comparing adjacent elements and merging them in the correct order.

This process continues until we obtain sorted sublists.

3. Combine: The sorted sublists are merged together to form a single sorted list. This is done by comparing elements from each sublist and placing them in the correct order.

## Illustration of Merge Sort

To better understand how Merge Sort works, let’s consider an example with an unsorted list: [8, 3, 5, 4, 1, 9].

We start by dividing this list into smaller sublists:

• [8] [3] [5] [4] [1] [9]

We then merge adjacent pairs of sublists together and sort them:

• [3, 8] [4, 5] [1, 9]

We repeat this process until we obtain a single sorted list:

• [1, 3, 4, 5, 8, 9]

Merge Sort has several advantages over other sorting algorithms:

• Efficiency: Merge Sort has a time complexity of O(n log n), making it efficient for large datasets.
• Stability: Merge Sort is a stable sorting algorithm, meaning that the relative order of equal elements is maintained during the sorting process.
• Divide-and-Conquer: The divide-and-conquer technique used in Merge Sort allows for efficient problem-solving by breaking down complex problems into simpler subproblems.

## Conclusion

Merge Sort is a highly efficient and stable sorting algorithm that utilizes the divide-and-conquer technique. By dividing the unsorted list into smaller sublists, sorting them individually, and then combining them, Merge Sort achieves a sorted list with a time complexity of O(n log n). Its stability and efficiency make it a popular choice in various applications where sorting is required.