feat: Implement Trie Prefix Tree #256

Author: donghyeon95

implement-trie-prefix-tree/donghyeon95.java

@@ -0,0 +1,29 @@
+import java.util.HashMap;
+
+class Trie {
+	HashMap<String, Boolean> trie;
+	public Trie() {
+		trie = new HashMap<>();
+	}
+
+	public void insert(String word) {
+		StringBuilder sb = new StringBuilder();
+		for (char c: word.toCharArray()) {
+			sb.append(c);
+			trie.putIfAbsent(sb.toString(), false);
+		}
+		trie.put(sb.toString(), true);
+	}
+
+	public boolean search(String word) {
+		return trie.getOrDefault(word, false);
+	}
+
+	public boolean startsWith(String prefix) {
+		return trie.containsKey(prefix);
+	}
+}
+
+
+
+