for (i = num/2; i>0; i = i/2) {
	for (j = i; j < num; j++) {
    	for(k = j-i; k >= 0; k = k-i) {

			if (arr[k+i] < arr[k])

				tmp = arr[k];
                arr[k] = arr[k+i];
                arr[k+i] = tmp;

			else {
                    break;
                }