java实现的排序(插入/希尔/归并)

java实现三种简单的排序,以下是代码:

/*插入排序*/
public static void insertionSort(int[] a)
{
    int j;
    for(int p = 1; p < a.length; p++)
    {
        int tmp = a[p];
        for(j = p; j > 0 && tmp < a[j - 1]; j--)
            a[j] = a[j - 1];
        a[j] = tmp;
    }

}
//-----------------------------------------------------------  keleyi.com
/*希尔排序*/
public static void shellsort(int[] a)
{
    int j;

    for(int gap = a.length / 2; gap > 0; gap /= 2)
        for(int i = gap; i < a.length; i++)
        {
            int tmp = a[i];
            for(j = i; j >= gap && tmp < a[j - gap]; j-=gap)
                a[j] = a[j - gap];
            a[j] = tmp;
        }
}
//-----------------------------------------------------------
/*归并排序*/
private static void mergeSort(int []a, int []tmpArray, int left, int right)
{
    if(left < right)
    {
        int center = (left + right) / 2;
        mergeSort(a, tmpArray, left, center);
        mergeSort(a, tmpArray, center + 1, right);
        merge(a, tmpArray, left, center + 1, right);
    }
}
public static void mergeSort(int []a)
{
    mergeSort(a, tmpArray, 0, a.length - 1);
}