diff --git a/src/main/java/com/cool/hot100/graph/Trie.java b/src/main/java/com/cool/hot100/graph/Trie.java
new file mode 100644
index 0000000..ded9d9e
--- /dev/null
+++ b/src/main/java/com/cool/hot100/graph/Trie.java
@@ -0,0 +1,63 @@
+package com.cool.hot100.graph;
+
+import org.junit.Test;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @Author: Cool
+ * @Date: 2024/09/05/09:53
+ * DayNumber 1
+ * Hard 2
+ * Level ?
+ */
+public class Trie {
+
+    Trie[] children = new Trie[26];
+    boolean isEnd = false;
+
+
+    public Trie() {
+
+    }
+
+    public void insert(String word) {
+        Trie node = this;
+        char[] wordCharArray = word.toCharArray();
+        for (char c : wordCharArray) {
+            if (node.children[c - 'a'] == null) {
+                node.children[c - 'a'] = new Trie();
+            }
+            node = node.children[c - 'a'];
+        }
+        node.isEnd = true;
+    }
+
+    public boolean search(String word) {
+        Trie node = searchNode(word);
+        return node != null && node.isEnd;
+    }
+
+    public boolean startsWith(String prefix) {
+        Trie node = searchNode(prefix);
+        return node != null;
+    }
+
+    private Trie searchNode(String word) {
+        char[] wordCharArray = word.toCharArray();
+        Trie node = this;
+        for (char c : wordCharArray) {
+            if (node.children[c - 'a'] == null) {
+                return null;
+            }
+            node = node.children[c - 'a'];
+        }
+        return node;
+    }
+    @Test
+    public void test(){
+        Trie trie = new Trie();
+        trie.insert("hotdog");
+        trie.startsWith("dog");
+    }
+}