n-ary tree univalence

gistfile1.java

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


/* root with three children
			       O
			 /     |       \
		       O       O       O
	           /  / \ \            | \
	           O  O  O O           O  O
				      /
			       	     O
*/

public class Node {
	int value;
	List<Node> children;

		public Node(int val){
		value = val;
		children = new ArrayList<Node>();
	}

	static boolean isUnival(Node tree, Counter counter){
		if (tree == null) return false;
		boolean totalUnivalence = true;
		boolean localUnivalence = true;

		if (tree.children.isEmpty()){
			return true;
		}

		for ( Node child : tree.children) {
			boolean uniVal = isUnival(child, counter);
			if (uniVal) counter.add(1);
			totalUnivalence = totalUnivalence && uniVal ;
			if (child.value != tree.value) {
				localUnivalence = false;
			}
		}
		return totalUnivalence && localUnivalence;
	}
	public Counter getCounter() {
		return new Counter();
	}


	class Counter {
		int subtrees;
		public  Counter() {
			subtrees = 0;
		}
		public void add(int val) {
			subtrees+=val;
		}
	}
	public static void main(String[] args) {

		Node treeRoot = new Node(7);

		treeRoot.children.add(new Node(7));
		Node firstChild = treeRoot.children.get(0);
		firstChild.children.add(new Node(7));
		firstChild.children.add(new Node(7));
		firstChild.children.add(new Node(7));
		firstChild.children.add(new Node(7));


		treeRoot.children.add(new Node(7));
		treeRoot.children.add(new Node(7));
		Node thirdChild = treeRoot.children.get(2);
		thirdChild.children.add(new Node(7));
		thirdChild.children.add(new Node(7));
		thirdChild.children.get(0).children.add(new Node(7));

		Counter counter = treeRoot.getCounter();
		System.out.println(isUnival(firstChild, counter));

		System.out.println(counter.subtrees);
	}
}