여러 갈래 나무의 깊이를 두루 훑어보다

package test;
import java.util.List;

public class Node {

	protected int value;
	
	protected List sonList;
	
	public Node(int value,List sonList){
		this.value = value;
		this.sonList = sonList;
	}
	
}

package test;

import java.util.ArrayList;
import java.util.List;

public class TestNode {

	public static void main(String[] args) {
		List sonList = new ArrayList();// list
		List sonList11 = new ArrayList();// list
		List sonList31 = new ArrayList();// list
			Node node11 = new Node(11, null);
			Node node12 = new Node(12, null);
			Node node13 = new Node(13, null);
			sonList11.add(node11);
			sonList11.add(node12);
			sonList11.add(node13);
			Node node1 = new Node(1, sonList11);
			Node node2 = new Node(2, null);
			Node node3 = new Node(3, sonList31);
			sonList.add(node1);
			sonList.add(node2);
			sonList.add(node3);
			Node node31 = new Node(31, null);
			Node node32 = new Node(32, null);
			Node node33 = new Node(33, null);
			sonList31.add(node31);
			sonList31.add(node32);
			sonList31.add(node33);
		Node root = new Node(0, sonList);
		preOrder(root);
	}

	/**
	 * @   
	 * @ void
	 * @ 835890
	 * @ 2017 4 26 
	 */
	private static void preOrder(Node root) {
		if(root != null){
			System.out.print(root.value + " ");
			if(root.sonList != null){
				for (int i = 0; i < root.sonList.size(); i++) {
					preOrder(root.sonList.get(i));
				}
			}
		}
	}
	
}