Java-二进制插入排序，排除故障

Question

I have a task where I need sort an array using binary insertion sort. This is the solution I came up with, but it is too slow:

public static void binaryInsertionSort(int[] a) {
    int ins, i, j;
    int tmp;
    for (i = 1; i < a.length; i++) {
        ins = BinarySearch (a, 0, i, a[i]);
            if(ins < i) {
                tmp = a[i];
                for (j = i - 1; j >= ins; j--)
                    a[j+1] = a[j];
                a[ins] = tmp;
            } 
    }   
}

private static int BinarySearch(int[] a, int low, int high, int key) {

    int mid;
    if (low == high)
        return low;
    mid = low + ((high - low) / 2);
    if (key > a[mid])
        return BinarySearch (a, mid + 1, high, key);
    else if (key < a[mid])
        return BinarySearch (a, low, mid, key);
    return mid;

}

I was recommended to use System.arraycopy method which I have tried, but I do not understand why it is not working:

public static void binaryInsertionSort(int[] a) {
    int ins, i;
    int tmp = a[i];
    for (i = 1; i < a.length; i++) {
        ins = binarySearch (a, 0, i, a[i]);
            if(ins < i){
                System.arraycopy(a, ins, a, ins + 1, i - ins);
                a[ins] = tmp;
            } 
    }   
}

private static int binarySearch(int[] a, int low, int high, int key) {
    int mid;
    if (low == high)
        return low;
    mid = low + ((high - low) / 2);
    if (key > a[mid])
        return binarySearch (a, mid + 1, high, key);
    else if (key < a[mid])
        return binarySearch (a, low, mid, key);
    return mid;
}

Any assistance is helpful.

Answer 1

Well, in the meantime the answer was easier than I thought. I initialized the local variable in the wrong place. Instead of:

public static void binaryInsertionSort(int[] a) {
int ins, i, j;
**int tmp = a[i];**
    for (i = 1; i < a.length; i++) {
        ins = BinarySearch (a, 0, i, a[i]);
            if(ins < i){
                tmp = a[i];
                for (j = i - 1; j >= ins; j--)
                a[j+1] = a[j];
                a[ins] = tmp;
            } 
    }   
}

The correct way is to:

public static void binaryInsertionSort(int[] a) {
    int ins, i;
        for (i = 1; i < a.length; i++) {
            **int tmp = a[i];**
            ins = binarySearch (a, 0, i, a[i]);
                if(ins < i){
                    System.arraycopy(a, ins, a, ins + 1, i - ins);
                    a[ins] = tmp;
                } 
    }   
}

And it works (: