Sum of all vertical levels of a Binary Tree

// Java program for super ugly number
import java.io.*;
import java.util.*;

// Structure of a Tree node
class TreeNode
{
  int val = 0;
  TreeNode left;
  TreeNode right;

  TreeNode(int x)
  {
    val = x;
    left = right = null;
  }
}

class GFG {

  static Map<Integer, ArrayList<ArrayList<Integer>>> mp = new HashMap<Integer, ArrayList<ArrayList<Integer>>>(); 

  // Function to convert
  // binary number to decimal
  static int getDecimal(ArrayList<ArrayList<Integer> > arr)
  {

    // Sort the array on
    // the basis of the
    // first index i.e, height
    Collections.sort(arr, new Comparator<ArrayList<Integer>>() {    
      @Override
      public int compare(ArrayList<Integer> o1, ArrayList<Integer> o2) {
        return o1.get(0).compareTo(o2.get(0));
      }               
    });

    // Store the required
    // decimal equivalent
    // of the number
    int ans = 0;

    // Traverse the array
    for (int i = 0; i < arr.size(); i++)
    {
      ans <<= 1;
      ans |= arr.get(i).get(1);
    }

    // Return the answer
    return ans;
  }

  // Function to traverse the tree
  static void Traverse(TreeNode root, int hd, int ht)
  {

    // If root is NULL, return
    if (root == null)
      return;

    if(mp.containsKey(hd))
    {
      mp.get(hd).add(new ArrayList<Integer>(Arrays.asList(ht, root.val)));
    }
    else
    {
      mp.put(hd,new ArrayList<ArrayList<Integer>>());
      mp.get(hd).add(new ArrayList<Integer>(Arrays.asList(ht, root.val)));
    }

    // Make recursive calls to the left and
    // right subtree
    Traverse(root.left, hd - 1, ht + 1);
    Traverse(root.right, hd + 1, ht + 1);
  }

  // Function to calculate
  // sum of vertical levels
  // of a Binary Tree
  static void getSum(TreeNode root)
  {

    // Function Call to perform traverse the tree
    Traverse(root, 0, 0);

    // Store the required answer
    int ans = 0;

    // Get decimal values for each vertical level
    // and add it to ans
    for(Integer key : mp.keySet())
    {
      ans += getDecimal(mp.get(key));
    }

    // Print the answer
    System.out.print(ans);
  }

  // Driver code
  public static void main (String[] args)
  {
    TreeNode root = new TreeNode(1);
    root.left = new TreeNode(1);
    root.right = new TreeNode(0);
    root.left.left = new TreeNode(1);
    root.left.right = new TreeNode(0);
    root.right.left = new TreeNode(1);
    root.right.right = new TreeNode(0);

    // Function call to get the
    // sum of vertical level
    // of the tree
    getSum(root);
  }
}

// This code is contributed by avanitrachhadiya2155