problem 211: Design Add and Search Words Data Structure

python/design_add_and_search_words_data_structure.py

@@ -0,0 +1,37 @@
+class Trienode:
+    def __init__(self):
+        self.children = {}
+        self.word = False
+
+class WordDictionary:
+
+    def __init__(self):
+        self.root = Trienode()
+
+
+    def addWord(self, word: str) -> None:
+        ptr = self.root
+        for ch in word:
+            if ch not in ptr.children:
+                ptr.children[ch] = Trienode()
+            ptr = ptr.children[ch]
+        ptr.word = True
+
+
+    def search(self, word: str) -> bool:
+        def dfs(j, root):
+            curr = root
+            for i in range(j, len(word)):
+                ch = word[i]
+                if ch == ".":
+                    for child in curr.children.values():
+                        if dfs(i+1, child):
+                            return True
+                    return False
+                else:
+                    if ch not in curr.children:
+                        return False
+                    curr = curr.children[ch]
+            return curr.word
+        return dfs(0, self.root)
+