在java中实现合并排序

Question

我正在尝试在java中编写快速合并排序。我基本上复制了维基百科页面中的代码，但出于某种原因我似乎无法使其工作。我确定我看到了一些小错误，但我似乎无法找到它。

public static void mergeSort(double[] array, double[] temp, int first, int last)
{         
    if( last - first < 2)
    {// if the length of subarray is 1 return the array.
        return;
    }// else you recurse.

    int mid = (first + last)/2;

    mergeSort(array, temp,first, mid);// recursively split the array
    mergeSort(array, temp, mid , last);
    merge(array,temp,first,mid,last);// merge the sorted halves
    copyArray(array, temp, first, last);
}// end of method merge sort

private static void merge(double[] array, double[] temp, int first, int mid ,int last)
{
    //  left half is A[first...mid-1]
    // right half is A[mid...last -1]
    int index0 = first, index1 = mid;

    for(int i = first; i < last;i++)
    {
        if(index0 <= mid && (index1 <= last || array[index0] <= array[index1]))
        {
            temp[i]= array[index0];
            index0+=1;
        }
        else
        {
            temp[i] = array[index1];
            index1+=1;
        }// end else
    }// end for       
}// end of method merge

public static void copyArray(double[] array, double[]temp, int first, int last)
{
    for(int i = first;i< last;i++)
    {
        array[i] = temp[i];
    }// end for        
}// end of method copyArray

这是我的输入

double [] array = {7,4,9,3,4,1,6,8,2,5};
double [] temp = new double[10];

mergeSort(array, temp, 0, 10);
System.out.println(Arrays.toString(array));

这是我的输出。

[7.0, 4.0, 9.0, 9.0, 3.0, 1.0, 1.0, 6.0, 8.0, 8.0]

有什么想法可以让它像这样加倍？