import java.util.LinkedList;

public class LevelOrder

{

public void levelIterator(BiTree root)

{

if(root == null)

{

return ;

}

LinkedList<BiTree> queue = new LinkedList<BiTree>();

BiTree current = null;

queue.offer(root);//將根節點入隊

while(!queue.isEmpty())

{

current = queue.poll();//出隊隊頭元素並訪問

System.out.print(current.val +"-->");

if(current.left != null)//如果當前節點的左節點不為空入隊

{

queue.offer(current.left);

}

if(current.right != null)//如果當前節點的右節點不為空，把右節點入隊

{

queue.offer(current.right);

}

}

}

}