Selection Sort Explained: How It Works, When to Use It, and Its Limits

Selection sort is a basic sorting algorithm that repeatedly scans an unsorted list, finds the smallest element, and moves it to the front of a growing sorted section. For a list of n items, the algorithm always performs n-1 passes and a fixed n(n-1)/2 comparisons, giving it O(n²) time complexity in all cases — best, average, and worst. Unlike bubble sort, it cannot detect an already-sorted list and skip unnecessary work. However, selection sort performs at most n-1 swaps total, making it useful in memory-constrained environments like flash storage where write operations are costly. Beyond such niche hardware use cases, the algorithm is primarily taught in classrooms and interviews as a stepping stone toward understanding more efficient sorting methods.