208 prefix solution

208-240525-pass/main1.py

@@ -0,0 +1,42 @@
+class TrieNode:
+    def __init__(self, val = ''):
+        self.child = []
+        self.is_word = False
+        self.val = val
+        self.child_map = {}
+class Trie:
+    def __init__(self):
+        self.root = TrieNode()
+
+    def insert(self, word: str) -> None:
+        parent_node = self.root
+        for idx, letter in enumerate(word):
+            if letter not in parent_node.child_map:
+                new_node = TrieNode(letter)
+                parent_node.child.append(new_node)
+                parent_node.child_map[letter] = len(parent_node.child) - 1
+                parent_node = new_node
+            else:
+                idx = parent_node.child_map[letter]
+                parent_node = parent_node.child[idx]
+        parent_node.is_word = True
+
+    def search(self, word: str) -> bool:
+        parent_node = self.root
+        for idx, letter in enumerate(word):
+            if letter not in parent_node.child_map:
+                return False
+            idx = parent_node.child_map[letter]
+            parent_node = parent_node.child[idx]
+        if parent_node.is_word == False:
+            return False
+        return True
+
+    def startsWith(self, prefix: str) -> bool:
+        parent_node = self.root
+        for idx, letter in enumerate(prefix):
+            if letter not in parent_node.child_map:
+                return False
+            idx = parent_node.child_map[letter]
+            parent_node = parent_node.child[idx]
+        return True