class Trie {
    Map<Character, Trie> children;
    boolean isWord;

    public Trie() {
        this.children = new HashMap<>();
        this.isWord = false;
    }

    public void insert(String word) {
        Trie current = this;
        for (char c: word.toCharArray()) {
            current.children.putIfAbsent(c, new Trie());
            current = current.children.get(c);
        }
        current.isWord = true;
    }

    public boolean search(String word) {
        Trie current = this;
        for (char c: word.toCharArray()) {
            if (!current.children.containsKey(c)) {
                return false;
            }
            current = current.children.get(c);
        }
        return current.isWord;
    }

    public boolean startsWith(String prefix) {
        Trie current = this;
        for (char c: prefix.toCharArray()) {
            if (!current.children.containsKey(c)) {
                return false;
            }
            current = current.children.get(c);
        }
        return true;
    }
}
/**
 * Your Trie object will be instantiated and called as such:
 * Trie obj = new Trie();
 * obj.insert(word);
 * boolean param_2 = obj.search(word);
 * boolean param_3 = obj.startsWith(prefix);
 */