java-作业-比较4种(Array-Sort、Insertion-Sort、Selection-Sort、Bubble

本篇主要为记录参加学校资讯班的作业，相关思考难点的纪录。
题目为比较4种sort演算法(Array-Sort、Insertion-Sort、Selection-Sort、Bubble-Sort)的执行速度，考虑不同排列会有不同的时间，本次设计取3次时间的平均值。

思考点：

先理解Insertion-Sort、Selection-Sort、Bubble-Sortsort的运作方式，并拆解后呈现出来。计算运算的时间并同时呈现进度条。优化，本篇很明显在描述4种排列法的时间计算时，几乎要用上3层迴圈了QQ，只是没写出来。

import java.util.Arrays;public class PerformanceBenchmarkforSortingAlgorithms {public static void main(String[] args) {int size[] = { 1000, 2000, 4000, 8000, 16000, 32000, 64000 };System.out.print("Simulating ArraySort：");double[] Amin = new double[size.length];for (int times = 0; times < size.length; times++) {int[] test = new int[size[times]];double[] result = new double[3];          //同样的资料数量，算3次for (int i = 0; i < 3; i++) {test = sample(test);                      //reset资料变回乱数double A000 = System.nanoTime()/1e6 ;ArraySort(test);                          // 呼叫method-ArraySortdouble A001 = System.nanoTime()/1e6 ;result[i] = (A001 - A000);                //将每一次的时间存起来};System.out.printf("．");                       //显示执行进度Amin[times] = (result[0] + result[1] + result[2])/3;   //3次平均};System.out.println("done");System.out.print("Simulating InsertionSort：");double[] Imin = new double[size.length];for (int times = 0; times < size.length; times++) {int[] test = new int[size[times]];double[] result = new double[3];for (int i = 0; i < 3; i++) {test = sample(test);double I000 = System.nanoTime()/1e6;InsertionSort(test);                    // 呼叫method-InsertionSortdouble I001 = System.nanoTime()/1e6;result[i] = (I001 - I000);};System.out.printf("．");Imin[times] = (result[0] / 3 + result[1] / 3 + result[2] / 3);};System.out.println("done");System.out.print("Simulating SelectionSort：");double[] Smin = new double[size.length];for (int times = 0; times < size.length; times++) {int[] test = new int[size[times]];double[] result = new double[3];for (int i = 0; i < 3; i++) {test = sample(test);double I000 = System.nanoTime()/1e6;SelectionSort(test);                  // 呼叫method-SelectionSortdouble I001 = System.nanoTime()/1e6;result[i] = (I001 - I000);};System.out.printf("．");Smin[times] = (result[0] / 3 + result[1] / 3 + result[2] / 3);};System.out.println("done");System.out.print("Simulating BubbleSort：");double[] Bmin = new double[size.length];for (int times = 0; times < size.length; times++) {int[] test = new int[size[times]];double[] result = new double[3];for (int i = 0; i < 3; i++) {test = sample(test);double I000 = System.nanoTime()/1e6;BubbleSort(test);                       // 呼叫method-BubbleSortdouble I001 = System.nanoTime()/1e6;result[i] = (I001 - I000);};System.out.printf("．");Bmin[times] = (result[0] / 3 + result[1] / 3 + result[2] / 3);};System.out.println("done");System.out.println("Benchmark (time unit: ms)");System.out.printf("%5s%23s%20s%20s%19s", "size", "BubbleSort", "SelectionSort", "InsertionSort", "ArraySort");System.out.println();for (int i = 0; i < size.length; i++) {System.out.printf("%5d%20.3f%20.3f%20.3f%20.3f", size[i], (double) Bmin[i], (double) Smin[i],(double) Imin[i], (double) Amin[i]);System.out.println();}}public static int[] sample(int[] num) {                //生成乱数的排列int[] a = num;for (int i = 0; i < a.length; i++) {a[i] = i;};for (int i = 0; i < a.length; i++) {int j = (int) (Math.random() * (a.length - i) + i);int temp = a[i];a[i] = a[j];a[j] = temp;};return a;}public static int[] ArraySort(int[] array01) {int[] A = array01;Arrays.sort(A);return A;}public static int[] BubbleSort(int[] array01) {int[] A = array01;boolean swapped;do {swapped = false;for (int i = 0; i < A.length - 1; i++) {if (A[i] > A[i + 1]) {int temp = A[i];A[i] = A[i + 1];A[i + 1] = temp;swapped = true;};};} while (swapped);return A;}public static int[] SelectionSort(int[] array01) {int[] A = array01;for (int j = 0; j < A.length; j++) {int min = j;for (int i = 0; i < A.length; i++) {if (A[min] > A[i]) {min = i;};int temp;temp = A[j];A[j] = A[min];A[min] = temp;};};return A;}public static int[] InsertionSort(int[] array01) {int[] A = array01;for (int i = 0; i < A.length; i++) {int index = i;while (index > 0 && A[index - 1] >= A[index]) {int tmp = A[index - 1];A[index - 1] = A[index];A[index] = tmp;index -= 1;       //继续向左边比大小；当index为0的时候，代表已经排到最小了，loop停止}}return A;}}

参考文章：

Comparison Sort: Insertion Sort(插入排序法)：http://alrightchiu.github.io/SecondRound/comparison-sort-insertion-sortcha-ru-pai-xu-fa.html