Find the common extent. That is, if one list has 20 grocery items, and the other has only 13, then the common extent is 13 grocery items. We can compare only the first 13 grocery items of each list. Find the first grocery item in the common extent that is different using three-way comparison (e.g., gItem1 gItem2 != 0) and return the results. If no differences were found in the common extent, then the list with the smaller size is less than the other. In that case, return the results of three-way comparing the sizes.