function PrintFromTopToBottom(root)
{
    // write code here
    let arr = []
    let data = []
    if(root!=null){
        arr.push(root)
    }
     while(arr.length!=0){
        var node=arr.shift();
        if(node.left!=null){
            arr.push(node.left);
        }
        if(node.right!=null){
            arr.push(node.right);
        }
        data.push(node.val);
    }
    return data;
}
module.exports = {
    PrintFromTopToBottom : PrintFromTopToBottom
};