feat: implement-trie-prefix-tree

Author: minji-go

implement-trie-prefix-tree/minji-go.java

@@ -0,0 +1,44 @@
+/**
+ * <a href="https://leetcode.com/problems/implement-trie-prefix-tree/">week05-3.implement-trie-prefix-tree</a>
+ * <li>Description: Implement the Trie class    </li>
+ * <li>Topics: Hash Table, String, Design, Trie </li>
+ * <li>Time Complexity: O(N*K), Runtime 40ms    </li>
+ * <li>Space Complexity: O(N*K), Memory 56.07MB  </li>
+ */
+class Trie {
+    private boolean end;
+    private final Map<Character, Trie> children;
+
+    public Trie() {
+        children = new HashMap<>();
+    }
+
+    public void insert(String word) {
+        Trie node = this;
+        for(Character c : word.toCharArray()) {
+            node = node.children.computeIfAbsent(c, k -> new Trie());
+        }
+        node.end = true;
+    }
+
+    public boolean search(String word) {
+        Trie node = this;
+        for(Character c : word.toCharArray()) {
+            node = node.children.get(c);
+            if(node == null) {
+                return false;
+            }
+        }
+        return node.end;
+    }
+
+    public boolean startsWith(String prefix) {
+        Trie node = this;
+        for(Character c : prefix.toCharArray()) {
+            node = node.children.get(c);
+            if(node == null) {
+                return false;
+            }
+        }
+        return node != null;
+    }