Merge Sort
Merge Sort is a divide-and-conquer sorting algorithm that recursively splits an array into halves, sorts each half, and then merges the sorted halves back together. It is known for its stable sorting behavior and consistent O(n log n) time complexity in all cases (best, average, and worst). This makes it particularly efficient for large datasets and is widely used in practice for sorting linked lists and external sorting scenarios.
Developers should learn Merge Sort when they need a reliable, efficient sorting algorithm for large or complex data, especially where stability (preserving the relative order of equal elements) is important. It is commonly used in applications like database management systems, file sorting, and as a foundational algorithm in computer science education to illustrate divide-and-conquer principles. Its predictable performance avoids the worst-case pitfalls of algorithms like Quick Sort.