Explain Multiway Merge sort with an example. Also discuss the need for sorting. What do you mean by sorting? Describe the need for sorting.

Q.) Explain Multiway Merge sort with an example. Also discuss the need for sorting. What do you mean by sorting? Describe the need for sorting.

 Subject: Data Structures

Answer:

Sorting is a process of arranging items systematically, and it has two types of order i.e., ascending and descending. The primary purpose of sorting is to make the data search easier and quicker.

There are several sorting algorithms available, and one of them is the Multiway Merge Sort.

Multiway Merge Sort is an algorithm that combines more than two sorted lists into a single sorted list. It is an extension of the standard merge sort algorithm, which only merges two lists at a time. The Multiway Merge Sort algorithm is more efficient when dealing with large data sets that are stored in external storage such as a hard disk.

Here is a step by step approach to the Multiway Merge Sort algorithm:

  1. Step 1: Divide the unsorted list into N sublists, each containing one element (a list of one element is considered sorted).

  2. Step 2: Repeatedly merge sublists to produce new sorted sublists until there is only one sublist remaining. This will be the sorted list.

Let's take an example to understand this better:

Suppose we have 4 sorted lists:

List 1: 10, 15, 30
List 2: 12, 15, 20
List 3: 17, 20, 32
List 4: 17, 19, 27

We will merge these lists in pairs:

Merge List 1 and List 2:

Result: 10, 12, 15, 15, 20, 30

Merge List 3 and List 4:

Result: 17, 17, 19, 20, 27, 32

Now, merge the resulting lists:

Final Result: 10, 12, 15, 15, 17, 17, 19, 20, 27, 30, 32

So, the final sorted list is: 10, 12, 15, 15, 17, 17, 19, 20, 27, 30, 32

Need for Sorting:

Sorting is fundamental to many computer applications, including:

  1. Search: Sorting can make searching for values in a dataset much more efficient.

  2. Database Systems: Databases use sorting to present data in a meaningful order (e.g., alphabetical, numerical, chronological).

  3. Data Analysis: Sorting can help identify patterns and make sense of data.

  4. Computer Graphics: Sorting is used in rendering scenes.

  5. Machine Learning: Many machine learning algorithms require the input data to be sorted.

In conclusion, sorting is a fundamental operation in computer science and has a wide range of applications. Multiway Merge Sort is an efficient sorting algorithm, especially when dealing with large datasets.