[mypy] Fix type annotations for trie.py (#5022)

* Fix type annotations for trie.py * Add strict type annotations to trie.py Annotate return type for all functions and type for "nodes" * updating DIRECTORY.md * Format trie.py Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: archaengel

data_structures/trie/trie.py

@@ -7,11 +7,11 @@
 
 
 class TrieNode:
- def __init__(self):
- self.nodes = dict() # Mapping from char to TrieNode
+ def __init__(self) -> None:
+ self.nodes: dict[str, TrieNode] = dict() # Mapping from char to TrieNode
  self.is_leaf = False
 
- def insert_many(self, words: list[str]):
+ def insert_many(self, words: list[str]) -> None:
  """
  Inserts a list of words into the Trie
  :param words: list of string words
@@ -20,7 +20,7 @@ def insert_many(self, words: list[str]):
  for word in words:
  self.insert(word)
 
- def insert(self, word: str):
+ def insert(self, word: str) -> None:
  """
  Inserts a word into the Trie
  :param word: word to be inserted
@@ -46,14 +46,14 @@ def find(self, word: str) -> bool:
  curr = curr.nodes[char]
  return curr.is_leaf
 
- def delete(self, word: str):
+ def delete(self, word: str) -> None:
  """
  Deletes a word in a Trie
  :param word: word to delete
  :return: None
  """
 
- def _delete(curr: TrieNode, word: str, index: int):
+ def _delete(curr: TrieNode, word: str, index: int) -> bool:
  if index == len(word):
  # If word does not exist
  if not curr.is_leaf:
@@ -75,7 +75,7 @@ def _delete(curr: TrieNode, word: str, index: int):
  _delete(self, word, 0)
 
 
-def print_words(node: TrieNode, word: str):
+def print_words(node: TrieNode, word: str) -> None:
  """
  Prints all the words in a Trie
  :param node: root node of Trie
@@ -89,7 +89,7 @@ def print_words(node: TrieNode, word: str):
  print_words(value, word + key)
 
 
-def test_trie():
+def test_trie() -> bool:
  words = "banana bananas bandana band apple all beast".split()
  root = TrieNode()
  root.insert_many(words)
@@ -112,11 +112,11 @@ def print_results(msg: str, passes: bool) -> None:
  print(str(msg), "works!" if passes else "doesn't work :(")
 
 
-def pytests():
+def pytests() -> None:
  assert test_trie()
 
 
-def main():
+def main() -> None:
  """
  >>> pytests()
  """