feat: implement-trie-prefix-tree

Author: junbinding

trie.implement-trie-prefix-tree.py

@@ -0,0 +1,64 @@
+class Trie:
+    """
+    208. 实现 Trie (前缀树)
+    https://leetcode-cn.com/problems/implement-trie-prefix-tree/
+    实现一个 Trie (前缀树)，包含 insert, search, 和 startsWith 这三个操作。
+    """
+    def __init__(self):
+        """
+        Initialize your data structure here.
+        """
+        self.lookup = {}
+
+
+    def insert(self, word: str) -> None:
+        """
+        Inserts a word into the trie.
+        """
+        tree = self.lookup
+        for a in word:
+            if a not in tree:
+                tree[a] = {}
+
+            tree = tree[a]
+        tree['#'] = '#'
+
+
+    def search(self, word: str) -> bool:
+        """
+        Returns if the word is in the trie.
+        """
+        tree = self.lookup
+        for a in word:
+            if a not in tree:
+                return False
+
+            tree = tree[a]
+
+        if '#' in tree:
+            return True
+
+        return False
+
+
+    def startsWith(self, prefix: str) -> bool:
+        """
+        Returns if there is any word in the trie that starts with the given prefix.
+        """
+        tree = self.lookup
+        for a in prefix:
+            if a not in tree:
+                return False
+
+            tree = tree[a]
+
+        return True
+
+
+trie = Trie()
+trie.insert("apple")
+trie.search("apple")
+trie.search("app")
+trie.startsWith("app")
+trie.insert("app")
+trie.search("app")