Make a set prefix-free

Question

Is there a standard or best algorithm to make a given set of strings prefix-free? That is, given a set of strings, throw out all strings that have a (shorter) prefix also in that set.

In case it matters, I'm ultimately gonna implement this in Python 2.7.

Answer 1

strings = ['a', 'apple', 'b', 'beta', 'c', 'd']

def prefices_only(strlist):
    ordered = sorted(strlist)
    last = ordered[0]
    results = [last]

    for c in ordered:
        if not c.startswith(last):
            last = c
            results.append(c)

    return results

print(prefices_only(strings))