Selection Sort Algorithm

Selection Sort algorithm is a simple comparison-based sorting technique that works by dividing the input list into two parts: sorted and unsorted. Initially, the sorted part is empty, and the unsorted part contains all the elements. The algorithm repeatedly selects the smallest (or largest, depending on the ordering) element from the unsorted part and moves it to the end of the sorted part. This process continues until the unsorted part becomes empty, and the sorted part contains all the elements in the desired order. In each iteration of the selection sort algorithm, the minimum (or maximum) element is identified from the remaining unsorted elements, and its position is swapped with the first unsorted element. This results in the minimum (or maximum) element moving to its correct position in the sorted part. The algorithm's time complexity is O(n^2) as it requires two nested loops in its implementation, making it inefficient for large datasets. However, it has the advantage of performing fewer swaps compared to other sorting algorithms like bubble sort, which might be beneficial in situations where swapping elements is a costly operation.
/*
 * Copyright (c) 2017 Kotlin Algorithm Club
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.algorithmexamples.sorts

/**
 * Selection sort is a simple sorting algorithm dividing the input list into two parts: the sublist of items already
 * sorted, which is built up from left to right at the front (left) of the list, and the sublist of items remaining
 * to be sorted that occupy 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 (or largest, depending on sorting order)
 * element in the unsorted sublist, exchanging (swapping) it with the leftmost unsorted element
 * (putting it in sorted order), and moving the sublist boundaries one element to the right.
 */
@ComparisonSort
@UnstableSort
class SelectionSort : AbstractSortStrategy() {
    public override fun<T : Comparable<T>> perform(arr: Array<T>) {
        for (i in arr.indices) {
            var min = i
            for (j in i + 1 until arr.size) {
                if (arr[j] < arr[min]) {
                    min = j
                }
            }
            if (min != i) arr.exch(min, i)
        }
    }
}

LANGUAGE:

DARK MODE: