public class Q3 {

	public static void main(String[] args) {
		BinNode<Integer> t1 = build_tree_ok();
		BinNode<Integer> t2 = build_tree_notOk();

		//boolean res = onePath(t2);
		boolean res = yarik(t1);
		System.out.println(res);

	}


	public static boolean yarik(BinNode<Integer>t) {
		if(t.getLeft()==null && t.getRight()==null) {
			return true;
		}else {
			if(!(t.getLeft()==null)&&t.getRight()==null) {
				if(t.getLeft().getValue()==t.getValue()) {
					return yarik(t.getLeft());
				}else {
					return false;
				}else {
					if(t.getRight().getValue()==t.getValue()) {
						return yarik(t.getRight());
					}else {
						return false;
					}
				}
			}
		}
	}
	public static boolean isLeaf(BinNode<Integer> t) {
		if(t == null)
			return false;
		if(t.getLeft() == null && t.getRight() == null)
			return true;
		return false;
	}
	//correct solution part1
	private static boolean onePath(BinNode<Integer> t1) {
		boolean r = onePath2(t1, t1.getValue());
		return r;
	}
	//correct solution part2
	private static boolean onePath2(BinNode<Integer> t, int x) {
		if(t==null)
			return false;
		int val = t.getValue();
		if(val!=x)
			return false;
		if(isLeaf(t))
			return val==x;
		return onePath2(t.getLeft(), val) || onePath2(t.getRight(), val);

	}

	public static BinNode<Integer> build_tree_ok() {

		BinNode<Integer> nd1 = new BinNode<Integer>(2);
		nd1.setLeft(new BinNode<Integer>(1));

		BinNode<Integer> nd2 = new BinNode<Integer>(1);
		nd2.setLeft(new BinNode<Integer>(1));
		nd2.setRight(new BinNode<Integer>(2));
		nd2.getLeft().setRight(nd1);

		BinNode<Integer> nd3 = new BinNode<Integer>(1);
		nd3.setLeft(new BinNode<Integer>(1));
		nd3.setRight(new BinNode<Integer>(2));

		BinNode<Integer> nd4 = new BinNode<Integer>(1);
		nd4.setRight(new BinNode<Integer>(2));
		nd4.getRight().setRight(new BinNode<Integer>(1));
		nd4.setLeft(nd3);

		BinNode<Integer> root = new BinNode<Integer>(1);
		root.setRight(nd2);
		root.setLeft(nd4);

		return root;

	}
	public static BinNode<Integer> build_tree_notOk() {

		BinNode<Integer> nd1 = new BinNode<Integer>(1); nd1.setLeft(new
				BinNode<Integer>(1));

		BinNode<Integer> nd2 = new BinNode<Integer>(1); nd2.setLeft(new
				BinNode<Integer>(1)); nd2.setRight(new BinNode<Integer>(2));
				nd2.getLeft().setRight(nd1);

				BinNode<Integer> nd3 = new BinNode<Integer>(1); nd3.setLeft(new
						BinNode<Integer>(1)); nd3.setRight(new BinNode<Integer>(2));

						BinNode<Integer> nd4 = new BinNode<Integer>(1); nd4.setRight(new
								BinNode<Integer>(2)); nd4.getRight().setRight(new BinNode<Integer>(1));
								nd4.setLeft(nd3);

								BinNode<Integer> root = new BinNode<Integer>(2);

								root.setRight(nd2);
								root.setLeft(nd4);

								return root;

	}

}