Python snippet to remove any substrings of other strings in the list

remove_substrings.py

from collections import defaultdict

def remove_substrings(words):
    """Remove any substrings of other strings in the list.
    
    O(n) solution from...
    Source: http://stackoverflow.com/a/24049808/234233
    """
    longest = defaultdict(str)
    for word in words:                                 # O(n)
        for i in range(1, len(word) + 1):              # O(k)
            for j in range(len(word) - i + 1):         # O(k)
                subword = word[j:j + i]                # O(1)
                if len(longest[subword]) < len(word):  # O(1)
                    longest[subword] = word            # O(1)
    filtered_list = list(set(longest.values()))
    
    # Keep original order
    filtered_list = [s for s in words if s in filtered_list]
    return filtered_list