Prefix-Free Check

Problem

Return True when no codeword in the list is a prefix of another codeword. Duplicate codewords count as a violation because each is a prefix of the other. Empty and single-element lists are prefix-free.

Hint

Only compare each unordered pair once; startswith covers both directions.

Test cases

case 1

in: [["0","10","11"]]

expected: true

case 2

in: [["0","01"]]

expected: false

case 3

in: [["00","01","10","11"]]

expected: true

case 4

in: [["1","1"]]

expected: false

case 5

in: [[]]

expected: true

Starter codePython

def is_prefix_free(words):
    # Your code here
    pass

5 test cases · run your code against them in the editor