java将数组传递给排序方法以查找它们的执行时间
我被分配到这个项目，我需要找到不同阵列的执行时间。除了数组从选择排序移动到气泡、从气泡移动到插入和合并，我的代码工作得非常好。问题是，当我的数组（1-1000之间的随机数）被传递到选择排序，它会对其进行排序，而排序后的数组被传递到排序方法的其余部分。我试着再次检查代码，但找不到问题所在。我应该填充一个数组还是什么
任何帮助都将不胜感激
package sorting;
import java.util.Arrays;
import java.util.Random;
import java.lang.Math;
import java.io.*;
import java.util.*;
public class sorting {
public static void main(String[] args) {
double[] arr1 = getArray(10000);
double[] arr2 = getArray(20000);
double[] arr3 = getArray(40000);
double[] arr4 = getArray(80000);
System.out.println("Problem 1: Selection sort, Bubble sort, Insertion sort, and Merge sort with thier execution time");
System.out.println("");
System.out.printf("%12s%15s%15s%17s%13s\n", "Number of Elements |", "Selection Sort", "Bubble Sort", "Insertion Sort", "Merge Sort");
System.out.println("--------------------------------------------------------------------------------");
long b = System.currentTimeMillis();
long startTime = System.currentTimeMillis();
selectionSort(arr1);
long endTime = System.currentTimeMillis();
long executionTime = endTime - startTime;
System.out.printf("%11s", arr1.length);
System.out.printf("%18s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
bubbleSort(arr1);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
insertionSort(arr1);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
(new MergeSort()).mergeSort(arr1);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s\n", executionTime, " ms");
System.out.printf("%11s", arr2.length);
startTime = System.currentTimeMillis();
selectionSort(arr2);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%18s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
bubbleSort(arr2);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
insertionSort(arr2);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
(new MergeSort()).mergeSort(arr2);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s\n", executionTime, " ms");
System.out.printf("%11s", arr3.length);
startTime = System.currentTimeMillis();
bubbleSort(arr3);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%18s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
bubbleSort(arr3);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
insertionSort(arr3);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
(new MergeSort()).mergeSort(arr3);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s\n", executionTime, " ms");
System.out.printf("%11s", arr4.length);
startTime = System.currentTimeMillis();
bubbleSort(arr4);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%18s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
bubbleSort(arr4);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
insertionSort(arr4);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s", executionTime, " ms");
startTime = System.currentTimeMillis();
(new MergeSort()).mergeSort(arr4);
endTime = System.currentTimeMillis();
executionTime = endTime - startTime;
System.out.printf("%12s%2s\n", executionTime, " ms");
}
public static double[] getArray(int n){
double[] arr = new double[n];
for(int i=0; i<n; i++){
arr[i] = ((double)(Math.random()*1000));
}
return arr;
}
public static void selectionSort(double[] arr) {
for (int i = 0; i < arr.length - 1; i++) {
double min = arr[i];
int currentMin = i;
for (int j = i + 1; j < arr.length; j++) {
if (min > arr[j]) {
min = arr[j];
currentMin = j;
}
}
if (currentMin != i) {
arr[currentMin] = arr[i];
arr[i] = min;
}
}
}
public static double[] insertionSort(double[] arr) {
double temp;
for (int i = 1; i < arr.length; i++) {
for (int j = i; j > 0; j--) {
if (arr[j] < arr[j - 1]) {
temp = arr[j];
arr[j] = arr[j - 1];
arr[j - 1] = temp;
}
}
}
return arr;
}
public static double[] bubbleSort(double[] arr) {
double temp;
for (int i = 0; i < arr.length; i++) {
// bubble up
for (int j = 0; j < arr.length - 1 - i; j++) {
if (arr[j] > arr[j + 1]) {
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
return arr;
}
public static class MergeSort {
private double[] array;
private double[] temp;
private int length;
public double[] mergeSort(double[] arr) {
this.array = arr;
this.length = arr.length;
this.temp = new double[length];
merge1(0, length - 1);
return arr;
}
private void merge1(int left, double right) {
if (left < right) {
double middle = left + (right - left) / 2;
merge1(left, middle);
merge1((int) (middle + 1), right);
merge2(left, middle, right);
}
}
private void merge2(int left, double middle, double right) {
for (int i = left; i <= right; i++) {
temp[i] = array[i];
}
int i = left;
int j = (int) (middle + 1);
int k = left;
while (i <= middle && j <= right) {
if (temp[i] <= temp[j]) {
array[k] = temp[i];
i++;
} else {
array[k] = temp[j];
j++;
}
k++;
}
while (i <= middle) {
array[k] = temp[i];
k++;
i++;
}
}
}
}
这就是我得到的输出 问题1：选择排序、冒泡排序、插入排序和合并排序的执行时间较短
Number of Elements | Selection Sort Bubble Sort Insertion Sort Merge
Sort
----------------------------------------------------------------------------
10000 85 ms 31 ms 31 ms 16 ms
20000 385 ms 100 ms 123 ms 10 ms
40000 3085 ms 401 ms 347 ms 8 ms
80000 13231 ms 1972 ms 1484 ms 35 ms
共 (0) 个答案