Java 8 |数组 parallelSort()方法示例
原文:https://www . geesforgeks . org/Java-8-arrays-parallels art-method-with-examples/
Java 8 在 java.util.Arrays 类中引入了一个名为parallels art()的新方法。它使用数组元素的并行排序
并行测试()算法
1. The array is divided into sub-arrays and that
sub-arrays is again divided into their sub-arrays,
until the minimum level of detail in a set of array.
2. Arrays are sorted individually by multiple thread.
3. The parallel sort uses Fork/Join Concept for sorting.
4\. Sorted sub-arrays are then merged.
语法:
-
按升序排序数据:
``` public static void parallelSort(Object obj[])
```
-
按升序对指定范围内的数据进行排序:
public static void parallelSort(Object obj[], int from, int to)
优势: parallels art()方法使用多线程的概念，这使得排序比正常排序方法更快。
例
下面是说明数组使用的程序:
程序 1: 演示并行排序的使用
// Java program to demonstrate
// Arrays.parallelSort() method
import java.util.Arrays;
public class ParallelSort {
public static void main(String[] args)
{
// Creating an array
int numbers[] = { 9, 8, 7, 6, 3, 1 };
// Printing unsorted Array
System.out.print("Unsorted Array: ");
// Iterating the Elements using stream
Arrays.stream(numbers)
.forEach(n -> System.out.print(n + " "));
System.out.println();
// Using Arrays.parallelSort()
Arrays.parallelSort(numbers);
// Printing sorted Array
System.out.print("Sorted Array: ");
// Iterating the Elements using stream
Arrays.stream(numbers)
.forEach(n -> System.out.print(n + " "));
}
}
Output:
Unsorted Array: 9 8 7 6 3 1
Sorted Array: 1 3 6 7 8 9
时间复杂度为 O(nlogn)
程序 2: 演示并行排序的使用
// Java program to demonstrate impact
// of Parallel Sort vs Serial Sort
import java.util.Arrays;
import java.util.Random;
public class ParallelSort {
public static void main(String[] args)
{
// Creating an array
int numbers[] = new int[100];
// Iterating Loop till i = 1000
// with interval of 10
for (int i = 0; i < 1000; i += 10) {
System.out.println("\nFor iteration number: "
+ (i / 10 + 1));
// Random Int Array Generation
Random rand = new Random();
for (int j = 0; j < 100; j++) {
numbers[j] = rand.nextInt();
}
// Start and End Time of Arrays.sort()
long startTime = System.nanoTime();
// Performing Serial Sort
Arrays.sort(numbers);
long endTime = System.nanoTime();
// Printing result of Serial Sort
System.out.println("Start and End Time in Serial (in ns): "
+ startTime + ":" + endTime);
System.out.println("Time taken by Serial Sort(in ns): "
+ (endTime - startTime));
// Start and End Time of Arrays.parallelSort()
startTime = System.nanoTime();
// Performing Parallel Sort
Arrays.parallelSort(numbers);
endTime = System.nanoTime();
// Printing result of Parallel Sort
System.out.println("Start and End Time in parallel (in ns): "
+ startTime + ":" + endTime);
System.out.println("Time taken by Parallel Sort(in ns): "
+ (endTime - startTime));
System.out.println();
}
}
}
Output:
For iteration number: 1
Start and End Time in Serial (in ns): 3951000637977:3951000870361
Time taken by Serial Sort(in ns): 232384
Start and End Time in parallel (in ns): 3951000960823:3951000971044
Time taken by Parallel Sort(in ns): 10221
For iteration number: 2
Start and End Time in Serial (in ns): 3951001142284:3951001201757
Time taken by Serial Sort(in ns): 59473
Start and End Time in parallel (in ns): 3951001256643:3951001264039
Time taken by Parallel Sort(in ns): 7396
.
.
.
For iteration number: 99
Start and End Time in Serial (in ns): 3951050723541:3951050731520
Time taken by Serial Sort(in ns): 7979
Start and End Time in parallel (in ns): 3951050754238:3951050756130
Time taken by Parallel Sort(in ns): 1892
For iteration number: 100
Start and End Time in Serial (in ns): 3951050798392:3951050804741
Time taken by Serial Sort(in ns): 6349
Start and End Time in parallel (in ns): 3951050828544:3951050830582
Time taken by Parallel Sort(in ns): 2038
注意:不同的时间间隔将被打印，但平行排序将在正常排序之前完成。
环境: 2.6 GHz 英特尔酷睿 i7，java 版本 8
版权属于：月萌API www.moonapi.com，转载请注明出处
