Hackerrank , 30 Days of Code Challenges ( Day 21 - 23 Solutions)

Day 21: Generics  :
//Write your code here

static <E>  void printArray( E[] inputArray)
{
for( E e : inputArray)
    {
    System.out.println(""+e);
}

}

Day 22: Binary Search Trees  :

public static int getHeight(Node root){
    //Write your code here
      if(root ==null)
          return -1;
      int left=getHeight(root.left);
      int right=getHeight(root.right);
      return Math.max(left, right) + 1;
  }

Day 23: BST Level-Order Traversal   :

    static void levelOrder(Node root){
      //Write your code here
        Queue<Node> queue = new LinkedList<Node>();
        queue.add(root);
        while(queue.peek()!=null)
            {
            Node node =queue.remove();
            System.out.print(""+node.data+" ");
            if(node.left!=null)
                queue.add(node.left);
            if(node.right!=null)
                queue.add(node.right);
        }
    }