quicksort

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package runningtimealgorithm;

import java.util.Random;

/**
 *
 * @author elmaleek
 */
public class QuickSort {

    static void quickSort (int a[], int lo, int hi){
        //  lo adalah index bawah, hi adalah index atas
        //  dari bagian array yang akan di urutkan
        int i=lo, j=hi, h;
        int pivot=a[lo];

        //  pembagian
        do{
            while (a[i]<pivot) i++;
            while (a[j]>pivot) j--;
            if (i<=j)
            {
                h=a[i]; a[i]=a[j]; a[j]=h;//tukar
                i++; j--;
            }
        } while (i<=j);

        //  pengurutan
        if (lo<j) quickSort(a, lo, j);
        if (i<hi) quickSort(a, i, hi);
    }

    public static void main(String[] args) {
        Random rand = new Random();
        int n = rand.nextInt(100);
        n += 1;
        int[] arr = new int[100];
        System.out.println("Array Sebelum Quick Sort");
        for (int i = 0; i < arr.length; ++i) {
         arr[i] = rand.nextInt(100);
         System.out.println(arr[i]);
      }
        double start = System.nanoTime();
        quickSort(arr, 0, n-1);
        double end = System.nanoTime();

        System.out.println("");
        System.out.println("Array Setelah Quick Sort");
        for (int i = 0; i < arr.length; ++i) {
         System.out.println(arr[i]);
      }

      double elapsedTime = end - start;

      System.out.println("");
      double seconds = elapsedTime / 1000000000;
      System.out.println("Waktu dalam nanoseken: " +elapsedTime );
      System.out.println("Waktu dalam detik " +seconds );

    }

}