@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		final Tree other = (Tree) obj;
		if (!Arrays.equals(subtrees, other.subtrees))
			return false;
		if (val == null) {
			if (other.val != null)
				return false;
		} else if (!val.equals(other.val))
			return false;
		return true;
	}