Day 23: BST Level-Order Traversal

https://www.hackerrank.com/challenges/30-binary-trees/problem

<?php
class Node{
    public $left,$right;
    public $data;
    function __construct($data)
    {
        $this->left=$this->right=null;
        $this->data = $data;
    }
}
class Solution{
    public function insert($root,$data){
        if($root==null){
            return new Node($data);
        }
        else{
            if($data<=$root->data){
                $cur=$this->insert($root->left,$data);
                $root->left=$cur;
            }
            else{
                $cur=$this->insert($root->right,$data);
                $root->right=$cur;
            }
            return $root;
        }
    }

    public function levelOrder($root){
        //Write your code here
        $arr = array();

        $arr[] = $root;
        while(!empty($arr)) {
            $node = array_shift($arr);
            if(!empty($node->left)) {
                $arr[] = $node->left;
            }
            if(!empty($node->right)) {
                $arr[] = $node->right;
            }
            echo $node->data." ";
        }
    }

}//End of Solution
$myTree=new Solution();
$root=null;
$T=intval(fgets(STDIN));
while($T-->0){
    $data=intval(fgets(STDIN));
    $root=$myTree->insert($root,$data);
}
$myTree->levelOrder($root);
?>