Sorting lists

This approach uses the sorted() function to determine which list is shorter and which is longer. Knowing this information, one can implement a simplified version of the list manipulation approach.

SUBLIST = 1
SUPERLIST = 2
EQUAL = 3
UNEQUAL = 4

def sublist(list_one, list_two):
    if list_one == list_two:
        return EQUAL
    if not list_one:
        return SUBLIST
    if not list_two:
        return SUPERLIST

    shorter, longer = sorted((list_one, list_two), key=len)

    for index in range(len(longer) - len(shorter) + 1):
        if longer[index : index + len(shorter)] == shorter:
            return SUPERLIST if longer is list_one else SUBLIST

    return UNEQUAL

Here, the case of the lists being equal is checked first. Then the special cases of empty lists are handled, returning SUBLIST or SUPERLIST as necessary.

Once those simple cases are out of the way, the sorted() function is used with the keyword argument key set to the len() function. This makes sorted() sort the items according to their length.

Once sorted() does its work, we use multiple assignment to unpack the results into the shorter and longer variables. Then, for each slice of length len(shorter) in longer, we test if that slice is equal to shorter.

If we find such a slice, that means shorter is a sublist of longer. Then we use a conditional expression along with the is operator to return SUBLIST or SUPERLIST depending on which of the original lists is longer.

If we do not find such a slice, we can eliminate SUBLIST and SUPERLIST from the possible categories, thus the two lists must be UNEQUAL.