算法 归并排序

private static void mergeSort(int[] arr, int left, int rigint) {
    //二分到最小粒度
    if (arr == null || arr.length <= 1 || left >= rigint) {
        return;
    }
    //求出中间索引
    int mid = (rigint+left) / 2;
    //继续分[left,mid]
    mergeSort(arr, left, mid);
    //继续分[mid+1,right]
    mergeSort(arr, mid + 1, rigint);

    //副本left--rignt的长度
    int aux[] = new int[rigint - left + 1];
    //进行copy
    for (int i = left; i <= rigint; i++) {
        aux[i - left] = arr[i];
    }

    int i = left;
    int j = mid + 1;
    System.out.println("arr="+JSON.toJSONString(arr));
    for (int k = left; k <= rigint; k++) {
        if (i>mid){
            arr[k]=aux[j-left];
            j++;
        }else if (j>rigint){
            arr[k]=aux[i-left];
            i++;
        }else if (aux[i-left]<aux[j-left]){
            arr[k]=aux[i-left];
            i++;
        }else {
            arr[k]=aux[j-left];
            j++;
        }
    }
}