solve: design add search words data structure

Author: SamTheKorean

design-add-and-search-words-data-structure/samthekorean.py

@@ -0,0 +1,49 @@
+# n: number of words | m: length of the word
+# TC: O(n*m)
+# SC: O(n*m)
+
+
+class TrieNode:
+    def __init__(self):
+        self.children = {}  # Dictionary to store child TrieNodes
+        self.is_word = False  # Flag to indicate if a word ends at this node
+
+
+class WordDictionary:
+    def __init__(self):
+        # Initialize WordDictionary with a root TrieNode.
+        self.root = TrieNode()
+
+    def addWord(self, word):
+        # Add a word to the Trie.
+        current_node = self.root
+
+        # Traverse each character in the word
+        for character in word:
+            # Create a new TrieNode if the character doesn't exist in children
+            current_node = current_node.children.setdefault(character, TrieNode())
+
+        # Mark the end of the word at the last character's node
+        current_node.is_word = True
+
+    def search(self, word):
+
+        def dfs(node, index):
+            if index == len(word):
+                # If reached end of the word, check if current node marks the end of a word
+                return node.is_word
+
+            if word[index] == ".":
+                # Handle wildcard character '.': Try all possible children
+                for child in node.children.values():
+                    if dfs(child, index + 1):
+                        return True
+            elif word[index] in node.children:
+                # Regular character: Move to the next node
+                return dfs(node.children[word[index]], index + 1)
+
+            # If no match found, return False
+            return False
+
+        # Start DFS from the root of the Trie
+        return dfs(self.root, 0)