def recurse_generate(words: list,
trie: Trie,
square_size: int,
chosen_words_length=0) -> list:
if chosen_words_length >= square_size or square_size <= 1:
if check_solution_is_valid(words, square_size):
return words
return None
# build up the solution letter by letter
# on each iteration we check if the substring is a key inside the Trie
# if not a key then we know the current permutation is not a solution so return None
# loop through the characters
for i in range(chosen_words_length, square_size):
prefix = "".join(word[i] for word in words)
# using the soon to be deprecated function because it runs ~30% faster
if not trie.has_keys_with_prefix(prefix):
return None
prefix = "".join(word[chosen_words_length] for word in words)
# we use a prefix to dictate which key to start going over
for word in trie.iterkeys(prefix):
new_list = words + [word]
res = recurse_generate(new_list, trie, square_size,
chosen_words_length + 1)
if res:
return res
return None
