直接上代码

public boolean f(Node head){
	Queue<Node> queue = new LinkedList();
	queue.add(head);
	boolean res = false;
	whille(!queue.isEmpty()){
		Node help = queue.poll();
		if((res && (help.left != null || help.right != null)) || (help.left == null && help.right != null)){
			return false; 
		}
		if(help.left() != null){
			queue.add(help.left); 
		} 
		if(help.right() != null){
			queue.add(help.right); 
		} 
		if(help.left == null || help.right == null){
			 res = true;
		}
	}
	return true;
}