import java.util.ArrayList;

/**
 * Created by Bakytzhan_Manaspayev on 2/20/2017.
 */
public class Node {
    String id;
    ArrayList<Node> childs = new ArrayList<Node>();

    public Node(String id) {
        this.id = id;
    }

    Node addChild(Node child) {
        childs.add(child);
        return this;
    }

    Node find(String id) {
        if (this.id.equals(id)) {
            return this;
        }

        for (int i = 0; i < childs.size(); i++) {
            Node node = childs.get(i).find(id);
            if (node != null) {
                return node;
            }
        }
        return null;
    }

}



public class Main {
    public static void main(String[] args) {

        /*

        1
       / \
     1_1  1_2
     / \
 1_1_1  1_1_2


         */

        Node root = new Node("1");
        Node child_1_1 = new Node("1_1");
        Node child_1_2 = new Node("1_2");
        root.addChild(child_1_1).addChild(child_1_2);

        Node child_1_1_1 = new Node("1_1_1");
        Node child_1_1_2 = new Node("1_1_2");
        child_1_1.addChild(child_1_1_1).addChild(child_1_1_2);

        //finding node, via visitor pattern
        System.out.println(root.find("1_1_2").id);



    }
}