Merge Sort is a popular sorting algorithm that follows the divide-and-conquer approach to efficiently sort a list of elements. The algorithm works by recursively dividing the input array into smaller sub-arrays until each sub-array has only one element, which are inherently sorted. Then, it merges these sorted sub-arrays back together to produce a single sorted array. This merging process compares elements from the two sub-arrays and selects the smaller (or larger) element each time, effectively combining the two arrays into one sorted array. Merge Sort's efficiency lies in its time complexity of O(n log n), making it suitable for large datasets, and its ability to maintain stability, meaning elements with equal values remain in their original order after sorting. Additionally, Merge Sort's use of additional space for temporary arrays during the merging process ensures stability and contributes to its predictable performance. Overall, Merge Sort is a reliable and efficient sorting algorithm widely used in practice.

This pseudocode describes the Merge Sort algorithm, which recursively divides the input array into smaller sub-arrays until each sub-array has only one element. Then, it merges these sub-arrays back together in sorted order. This algorithm maintains a time complexity of O(n log n) and uses additional space for the temporary arrays during merging, also O(n).