/**
consider this example of 114. Flatten Binary Tree to Linked List, I'm creating new TreeNode from 
the root and returning the result in root i can verify the result is correct in debbugger but leetcode does not accept the 
answer instead it says the output is original tree. please help me with this.
*/
class Solution {
    public void flatten(TreeNode root) {    
         root = help(root);
        
    }
    
    public TreeNode help(TreeNode root){
        if(root == null){
            return null;
        }
        
        
      TreeNode r = help(root.right);
      TreeNode l =  help(root.left);

    TreeNode ans = new TreeNode(root.val);
        
      if(r == null && l == null){ 
      }
      else if (l == null){
          ans.right = r;
      }  
        
      else if(r == null){
            ans.right = l;
          
      }  
      else{
        
        TreeNode temp = l;
          
         while(temp.right != null){
             temp = temp.right;
         } 
        temp.right = r;
        ans.right = l;  
        
          
       } 
     
      return ans;
        
        
    }
}