updated with optimal solution

challenges/autocomplete-system.py

@@ -1,33 +1,73 @@
+#!/usr/bin/python
+""" #11
+Purpose: This problem was asked by Twitter.
+    Implement an autocomplete system. That is, given a query string s
+    and a set of all possible query strings, return all strings in the
+    set that have s as a prefix.
+Example: Given the query string de and the set of strings [dog, deer, deal],
+    return [deer, deal]
+Hint: Try pre-processing the dictionary into a more efficient data structure
+    to speed up queries
+
 """
-#11
-Twitter
 
-Implement an autocomplete system. That is, given a query string s and a set of all possible query strings,
-return all strings in the set that have s as a prefix.
 
-For example, given the query string de and the set of strings [dog, deer, deal], return [deer, deal].
+def time_taken(func):
+    def __inner(*args, **kwargs):
+        import time
+        start_time = time.perf_counter_ns()
+        _result = func(*args, **kwargs)
+        print(f'Execution time :{func.__name__} is {time.perf_counter_ns() - start_time :5} ns')
+        return _result
+
+    return __inner
+
+
+@time_taken
+def auto_complete_1(word_dict, query_string):
+    """
+
+    :param word_dict:
+    :param query_string:
+    :return:
+    """
+    matched_words = []
+    for each_word in word_dict:
+        if each_word.startswith(query_string):
+            matched_words.append(each_word)
+    return matched_words
+
+
+@time_taken
+def auto_complete_2(word_dict, query_string):
+    """
+
+    :param word_dict:
+    :param query_string:
+    :return:
+    """
+    return [each_word for each_word in word_dict if each_word.startswith(query_string)]
 
-Hint: Try preprocessing the dictionary into a more efficient data structure to speed up queries.
 
-"""
 suggestions = []
 
+
 class Node:
     def __init__(self, val):
         self.val = val
         self.children = []
-    
+
     def add(self, remaining, word):
         exists = False
-        
+
         for child in self.children:
             if remaining[0] == child.val:
                 exists = True
                 if len(remaining) > 1:
                     child.add(remaining[1:], word)
                 else:
                     child.children.append(Node(word))
-        
+
         if not exists:
             newNode = Node(remaining[0])
             self.children.append(newNode)
@@ -36,35 +76,37 @@ def add(self, remaining, word):
             else:
                 newNode.children.append(Node(word))
 
-    def findSuggestions(self):
-        if self.children == []:
-            suggestions.append(self.val)
-        else:
+    def find_suggestions(self):
+        if self.children:
             for child in self.children:
-                child.findSuggestions()
+                child.find_suggestions()
+        else:
+            suggestions.append(self.val)
 
     def find(self, query):
         if query == "":
-            self.findSuggestions()
+            self.find_suggestions()
             return
 
         for child in self.children:
             if query[0] == child.val:
                 return child.find(query[1:])
-        
+
         return None
 
 
-if __name__ == "__main__":
+@time_taken
+def auto_complete_3(word_dict, query_string):
     root = Node("root")
-
-    queryStrings = ["dog", "deer", "deal"]
-
-    for query in queryStrings:
+    for query in word_dict:
         root.add(query.lower(), query.lower())
 
-    query = "de"
+    root.find(query_string)
+
+    return suggestions
 
-    root.find(query)
 
-    print(suggestions)
+if __name__ == '__main__':
+    assert auto_complete_1(word_dict=['dog', 'deer', 'deal'], query_string='de') == ['deer', 'deal']
+    assert auto_complete_2(word_dict=['dog', 'deer', 'deal'], query_string='de') == ['deer', 'deal']
+    assert auto_complete_3(word_dict=['dog', 'deer', 'deal'], query_string='de') == ['deer', 'deal']