Python/strings/autocomplete_using_trie.py

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from __future__ import annotations
END = "#"
class Trie:
def __init__(self) -> None:
self._trie: dict = {}
def insert_word(self, text: str) -> None:
trie = self._trie
for char in text:
if char not in trie:
trie[char] = {}
trie = trie[char]
trie[END] = True
def find_word(self, prefix: str) -> tuple | list:
trie = self._trie
for char in prefix:
if char in trie:
trie = trie[char]
else:
return []
return self._elements(trie)
def _elements(self, d: dict) -> tuple:
result = []
for c, v in d.items():
sub_result = [" "] if c == END else [(c + s) for s in self._elements(v)]
result.extend(sub_result)
return tuple(result)
trie = Trie()
words = ("depart", "detergent", "daring", "dog", "deer", "deal")
for word in words:
trie.insert_word(word)
def autocomplete_using_trie(string: str) -> tuple:
"""
>>> trie = Trie()
>>> for word in words:
... trie.insert_word(word)
...
>>> matches = autocomplete_using_trie("de")
>>> "detergent " in matches
True
>>> "dog " in matches
False
"""
suffixes = trie.find_word(string)
return tuple(string + word for word in suffixes)
def main() -> None:
print(autocomplete_using_trie("de"))
if __name__ == "__main__":
import doctest
doctest.testmod()
main()