How does the selection sort algorithm function?

The selection sort algorithm sorts an array by repeatedly finding the minimum element and moving it to the beginning.

The selection sort algorithm is a simple comparison-based sorting algorithm. It works by dividing the input into a sorted and an unsorted region. The sorted region is initially empty, while the unsorted region contains all the elements. The algorithm repeatedly selects the smallest (or largest, depending on the ordering) element from the unsorted region and moves it to the end of the sorted region. This process continues until the unsorted region is empty and the sorted region contains all the elements in the correct order.

The algorithm begins by finding the minimum element in the unsorted region of the array and swapping it with the first element. This element then becomes part of the sorted region, while the rest of the array remains unsorted. The process is then repeated for the rest of the elements in the unsorted region, each time finding the minimum element and swapping it with the first element of the unsorted region. This continues until the entire array is sorted.

In terms of complexity, selection sort performs well for smaller lists as it maintains a simple linear search to find the minimum or maximum element. However, for larger lists, its performance decreases significantly. This is because it has a time complexity of O(n^2), where n is the number of items being sorted. This makes it inefficient on large lists, and generally performs worse than the similar insertion sort.

Despite its simplicity, selection sort is not often used in practice for large arrays, as other algorithms such as quicksort, heapsort, or merge sort are more efficient for larger lists. However, it has the advantage of being easy to understand and implement, making it a good choice for educational purposes or for sorting small arrays.

In summary, the selection sort algorithm is a simple, comparison-based sorting algorithm that works by repeatedly finding the minimum element from the unsorted region and moving it to the sorted region. It is easy to understand and implement, but not typically used for large arrays due to its O(n^2) time complexity.