Understanding - Advanced, exercise 11

Text

The variable my_gn contains the string of a given name in lowercase and without any space (e.g. "johnhenry"), the variable my_fn contains the string of a family name in lowercase and without any space (e.g. "doe"), and the variable my_mn contains the string of ten 0-9 digits. Study the execution of the following functions when they are called as follows: rs(my_gn, my_fn, my_mn, list()).

def rs(gn, fn, m, lst):
    if gn != "" and fn != "":
        if gn[0] < fn[0]:
            lst.append(int(m[0]))
        elif len(lst) > 1:
            v = lst[len(lst) - 1] * int(m[0])
            lst = lst[:len(lst) - 1] + [v]
        lst = rs(gn[1:], fn[1:], m[1:], lst)

    return lst

Hints

The recursive function rs populates the input list with the characters (considered one by one) included in the input digits according to the values of the characters in the given and family names.

Additional material

The runnable Python file is available online. You can run it executing the command python exercise_11.py in a shell, and then following the instructions on screen to specify the intended input.