Create autocomplete_using_trie.py (#1406)

* Create autocomplete_using_trie.py

The program aims to design a trie implementation for autocomplete which is easy to understand and ready to run.

* Removed unused import

* Updated the list value

* Update autocomplete_using_trie.py

* Run the code through Black and add doctest

other/autocomplete_using_trie.py

@@ -0,0 +1,64 @@
+END = "#"
+
+
+class Trie:
+    def __init__(self):
+        self._trie = {}
+
+    def insert_word(self, text):
+        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):
+        trie = self._trie
+        for char in prefix:
+            if char in trie:
+                trie = trie[char]
+            else:
+                return []
+        return self._elements(trie)
+
+    def _elements(self, d):
+        result = []
+        for c, v in d.items():
+            if c == END:
+                subresult = [" "]
+            else:
+                subresult = [c + s for s in self._elements(v)]
+            result.extend(subresult)
+        return tuple(result)
+
+
+trie = Trie()
+words = ("depart", "detergent", "daring", "dog", "deer", "deal")
+for word in words:
+    trie.insert_word(word)
+
+
+def autocomplete_using_trie(s):
+    """
+    >>> 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(s)
+    return tuple(s + w for w in suffixes)
+
+
+def main():
+    print(autocomplete_using_trie("de"))
+
+
+if __name__ == "__main__":
+    main()