Differences between Merge Sort and Bubble Sort

In the programming world, there are multiple solutions to a single problem and sorting is no exception. If you are not aware of what sorting is, it is a procedure of arranging the elements of a data structure in a certain order.

For example, we know that 1 comes before 2 or 2 comes before 3, thanks to the numerical systems. In such a way, the elements of a data structure also need to be sorted. In programming, sorting can be done in different ways. However, you need to choose the one which is suitable as per the data structure and the number of elements.

These sorting algorithms include bubble sort, quick sort, merge sort, insertion sort, and selection sort. For a lot of people, it can be confusing which algorithm to employ on the given data, and hence, understanding the use case of each is important. Here, we have come up with a detailed comparison between the merge sort and bubble sort for you.

## What Is Bubble Sort?

It is the easiest and simplest method of sorting. This works in a similar way to a bubble trying to get to the surface. In this method, with every iteration, the highest value among the array is found and it is then placed at the end of the list or wherever the element belongs according to other elements in the data set. Bubble sort focuses on sorting the elements closer to the left as after each iteration, it transfers the highest element on the right side and the lowest element to the left.

Other than this, the worst case of bubble sort is when the elements are arranged in reverse order. It will take more iterations to sort the elements. However, it is still better as the algorithm will decide in the initial iteration only that the data set is already sorted.

## What Is Merge Sort?

This sorting algorithm may not be the easiest one but it is definitely the fastest one. In this sorting algorithm, the larger data set is divided into smaller ones. After that, these smaller data sets are sorted. When these small data sets are sorted, they are merged together to form the larger and sorted data set.

The process of merging is easy because if the two data sets are sorted, it will be easy to compare the first elements of both the data sets. Among them, the data set which has the highest element will be placed on the right and the other one will be placed on the left.

## Key Differences Between Bubble Sort And Merge Sort

So, now that you are familiar with what bubble sort and merge sort are, here are the key differences between the two. We have taken different other factors into account to curate the difference between the two.

## Working With Small Data Sets

When it comes to working with smaller data sets, there is not much difference in the time taken by both algorithms. Both algorithms take almost a similar time in sorting the same set of data. There is no such predominant difference found in these two algorithms in this scenario.

## Complexity Of The Algorithm

A huge difference is observed between the complexity of the two algorithms. Suppose that you are given a data set of size “n”. Merge sort has a time complexity of O(n log n). While the bubble sort algorithm has a time complexity of O(n2) - 𝛀(n).

## Pseudo Code Analysis

Pseudocode analysis is one of the most important factors to consider while comparing any sorting algorithm. As per the pseudo-code of both merge sort and a bubble sort, it is observed that bubble sort follows an iterative process. Whereas, when it comes to the merge sort, it is more of a recursive process.

## Working With Larger Data Sets

As a programmer, you do not only need to work on smaller data sets. At times, the sorting algorithm that you may use to sort smaller datasets may not work for the larger data set. While working with larger data sets, it is recommended to use merge sort as it will take fewer memory units because of its recursive nature. Whereas, bubble sort will certainly take up a lot of space because of the iterative nature.

Space allotted for a process is an essential factor to consider while working with any type of data sets. With the increasing complexity of data, even 1000 sets of variables seem like a smaller number. Therefore, in the case of larger sets, it is beneficial to choose a merge sort instead of a bubble sort.

## Which Is Better: Merge Sort Or Bubble Sort?

After going through all the differences, it is no surprise if you are still not sure which one to choose. Deciding which sorting algorithm is better mainly depends on the data sets that you are given. Merge sort is more efficient than bubble sort but at the same time, it is a lot more complex too. However, bubble sort is an easier way of sorting but it may not work efficiently with larger data sets. So, for now, it can be concluded that when you are working with smaller data sets, you can use bubble sort as not many iterations are required. However, if you are working with larger data sets, choosing merge sort is the right decision.

## Conclusion

Sorting algorithms are life savers. Imagine how much time a person would take to sort so many elements. With sorting algorithms, 1000s of elements can be sorted in some seconds. However, it is important for you to analyze well which sorting algorithm you need to choose to sort a particular data set.

Choose between bubble sort and merge sort as per the data sets provided and keep all the key differences mentioned above in mind.

Whether you have an imminent interview or an exam, prep yourself up with the competitive problems including how to merge two sorted linked lists or how to sort the given data set.

These are some most asked questions in the competitive interviews of every tech firm. So, next time you are asked to sort the elements, you know which algorithm you have to choose.