Binary Tree vertical sum using doubly linked list (DLL)

Hint : Solution is based on horizontal distances

Latest Source Code:
Github: BinaryTreeVerticalSumUsingDLL.java

Output:

        20               
      / \       
     /   \      
    /     \     
   /       \    
   8       22       
  / \       \   
 /   \       \  
 4   12       25   
    / \         
    10 14         
                                
Sum : 4 18 32 36 25