Selection Sort

最后更新于:2022-04-02 01:06:45

# Selection Sort - 选择排序 核心:不断地选择剩余元素中的最小者。 1. 找到数组中最小元素并将其和数组第一个元素交换位置。 1. 在剩下的元素中找到最小元素并将其与数组第二个元素交换,直至整个数组排序。 性质: - 比较次数=(N-1)+(N-2)+(N-3)+...+2+1~N^2/2 - 交换次数=N - 运行时间与输入无关 - 数据移动最少 下图来源为 [File:Selection-Sort-Animation.gif - IB Computer Science](http://wiki.ibcsstudent.org/index.php?title=File:Selection-Sort-Animation.gif) ![Selection Sort](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2015-10-24_562b1f3177b83.gif) ### Implementation ### Python ~~~ #!/usr/bin/env python def selectionSort(alist): for i in xrange(len(alist)): print(alist) min_index = i for j in xrange(i + 1, len(alist)): if alist[j] < alist[min_index]: min_index = j alist[min_index], alist[i] = alist[i], alist[min_index] return alist unsorted_list = [8, 5, 2, 6, 9, 3, 1, 4, 0, 7] print(selectionSort(unsorted_list)) ~~~ ### Java ~~~ public class Sort { public static void main(String[] args) { int unsortedArray[] = new int[]{8, 5, 2, 6, 9, 3, 1, 4, 0, 7}; selectionSort(unsortedArray); System.out.println("After sort: "); for (int item : unsortedArray) { System.out.print(item + " "); } } public static void selectionSort(int[] array) { int len = array.length; for (int i = 0; i < len; i++) { for (int item : array) { System.out.print(item + " "); } System.out.println(); int min_index = i; for (int j = i + 1; j < len; j++) { if (array[j] < array[min_index]) { min_index = j; } } int temp = array[min_index]; array[min_index] = array[i]; array[i] = temp; } } } ~~~ ### Reference - [选择排序 - 维基百科,自由的百科全书](http://zh.wikipedia.org/wiki/%E9%80%89%E6%8B%A9%E6%8E%92%E5%BA%8F) - [The Selection Sort — Problem Solving with Algorithms and Data Structures](http://interactivepython.org/runestone/static/pythonds/SortSearch/TheSelectionSort.html)
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