Counting Sort
Counting Sort is a non-comparison-based integer sorting algorithm that operates by counting the number of objects that have each distinct key value, then using arithmetic to determine the positions of each key in the output sequence. It is efficient for sorting integers or objects with integer keys within a known, limited range, with a time complexity of O(n + k) where n is the number of elements and k is the range of the key values. The algorithm is stable, meaning it preserves the relative order of elements with equal keys.
Developers should learn Counting Sort when dealing with sorting tasks involving integers or data with small, known ranges, such as sorting ages, grades, or pixel values in image processing, as it can outperform comparison-based sorts like QuickSort or MergeSort in these scenarios. It is particularly useful in competitive programming, data analysis, and applications requiring stable sorting with predictable performance, but should be avoided for large ranges or non-integer data where it becomes inefficient.