valintasortauksen

Valintasortaus, also known as selection sort, is a simple comparison-based sorting algorithm. It works by repeatedly finding the minimum element from the unsorted part of the list and putting it at the beginning. This process is continued until the entire list is sorted.

The algorithm divides the input list into two parts: a sorted sublist which is built up from left to right at the front of the list, and a remaining unsorted sublist that occupies the rest of the list. Initially, the sorted sublist is empty, and the unsorted sublist is the entire input list. The algorithm proceeds by finding the smallest element in the unsorted sublist, exchanging it with the leftmost unsorted element, and moving the sublist boundary one element to the right.

This process is repeated for each position in the list. For a list of n elements, selection sort performs n-1 passes. In each pass, it iterates through the unsorted portion to find the minimum element. While simple to understand and implement, selection sort is not efficient for large datasets. Its time complexity is O(n^2) in all cases (best, average, and worst), making it unsuitable for performance-critical applications. It does, however, have a minimal number of swaps, which can be advantageous in scenarios where writing to memory is expensive.