Created a Trie implementation in Java

trie/Trie.txt

@@ -0,0 +1,62 @@
+private class Node {
+    String prefix;
+    HashMap<Character, Node> children;
+
+    // Does this node represent the last character in a word?
+    boolean isWord;
+
+    private Node(String prefix) {
+        this.prefix = prefix;
+        this.children = new HashMap<Character, Node>();
+    }
+}
+
+// The trie
+private Node trie;
+
+// Construct the trie from the dictionary
+public Autocomplete(String[] dict) {
+    trie = new Node("");
+    for (String s : dict) insertWord(s);
+}
+
+// Insert a word into the trie
+private void insertWord(String s) {
+    // Iterate through each character in the string. If the character is not
+    // already in the trie then add it
+    Node curr = trie;
+    for (int i = 0; i < s.length(); i++) {
+        if (!curr.children.containsKey(s.charAt(i))) {
+            curr.children.put(s.charAt(i), new Node(s.substring(0, i + 1)));
+        }
+        curr = curr.children.get(s.charAt(i));
+        if (i == s.length() - 1) curr.isWord = true;
+    }
+}
+
+// Find all words in trie that start with prefix
+public List<String> getWordsForPrefix(String pre) {
+    List<String> results = new LinkedList<String>();
+
+    // Iterate to the end of the prefix
+    Node curr = trie;
+    for (char c : pre.toCharArray()) {
+        if (curr.children.containsKey(c)) {
+            curr = curr.children.get(c);
+        } else {
+            return results;
+        }
+    }
+
+    // At the end of the prefix, find all child words
+    findAllChildWords(curr, results);
+    return results;
+}
+
+// Recursively find every child word
+private void findAllChildWords(Node n, List<String> results) {
+    if (n.isWord) results.add(n.prefix);
+    for (Character c : n.children.keySet()) {
+        findAllChildWords(n.children.get(c), results);
+    }
+}