Count the nodes at distance K from leaf

//User function Template for Java

// class Node  
// { 
//     int data; 
//     Node left, right; 
   
//     public Node(int d)  
//     { 
//         data = d; 
//         left = right = null; 
//     } 
// }

class Solution
{
    //Function to return count of nodes at a given distance from leaf nodes.
    int printKDistantfromLeaf(Node root, int k)
    {
        // Write your code here
        
        
        HashMap<Integer, Node> hm = new HashMap<>();
        HashSet<Node> hs = new HashSet<>();
        dfs(hm, hs, 1, k, root);
        return hs.size();

        
        
        
        
        
    }
    
    public void dfs(HashMap<Integer, Node> hm, HashSet<Node> hs, int l, int k, Node root)
    {
        if(root == null)
        {
            return;
            
        }
        
        hm.put(l, root);
        
        
        if(root.left == null && root.right == null)
        {
            if(k >=l) return;
            hs.add(hm.get(l-k));
        }
        
        dfs(hm, hs, l+1, k, root.left);
        dfs(hm, hs, l+1, k, root.right);
    
        
    }


}