希尔排序

    public static int[] ShellInsert(int[] arr){
        int step = arr.length/2;  
        while(step >= 1){
            for(int i=step;i<arr.length;i++){
                int temp = arr[i];
                int j = 0;
                for(j=i-step;j>=0 && temp<arr[j];j-=step){
                    arr[j+step] = arr[j];
                }
                arr[j+step] = temp;
            }
            step /= 2;
        }
        return arr;
    }