Explain the merge sort algorithm.

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Explain the merge sort algorithm.

The merge sort algorithm is a popular sorting algorithm that follows the divide-and-conquer approach. It works by dividing the unsorted list into smaller sublists, sorting those sublists, and then merging them back together to obtain a sorted list.

The merge sort algorithm can be explained in the following steps:

1. Divide: The unsorted list is divided into two equal halves repeatedly until each sublist contains only one element. This is done recursively until the base case is reached.

2. Conquer: Once the base case is reached (sublists with only one element), the merging process begins. The sublists are merged back together in a sorted order. This is done by comparing the elements of the sublists and placing them in the correct order.

3. Merge: The merging process involves comparing the elements of the two sublists and selecting the smaller element to be placed in the final sorted list. This process continues until all elements from both sublists are merged into the final sorted list.

4. Repeat: Steps 1 to 3 are repeated recursively until the entire list is sorted.

The merge sort algorithm has a time complexity of O(n log n), where n is the number of elements in the list. This makes it an efficient sorting algorithm for large datasets. Additionally, merge sort is a stable sorting algorithm, meaning that it preserves the relative order of equal elements.

One of the key advantages of merge sort is that it can handle large datasets efficiently due to its divide-and-conquer approach. It also has a predictable performance, regardless of the initial order of the elements. However, merge sort requires additional space to store the sublists during the sorting process, which can be a drawback for memory-constrained systems.

In conclusion, the merge sort algorithm is a divide-and-conquer sorting algorithm that efficiently sorts a list by dividing it into smaller sublists, sorting them, and then merging them back together. It has a time complexity of O(n log n) and is suitable for handling large datasets.