Maximum sum with out adjacent nodes

#include <bits/stdc++.h> 
/************************************************************

    Following is the TreeNode class structure

    template <typename T>
    class TreeNode {
       public:
        T data;
        TreeNode<T> *left;
        TreeNode<T> *right;

        TreeNode(T data) {
            this->data = data;
            left = NULL;
            right = NULL;
        }
    };

************************************************************/
#include <unordered_map> 

int helper(TreeNode <int> * root , unordered_map < TreeNode<int> * , int > &dp )
{
    if(root == NULL)
    {
        return 0 ; 
    }
    if(dp.count(root) > 0)
    {
        return dp[root] ;
    }
    int rr = 0  , rl = 0 , lr = 0 , ll = 0;
    if(root->left != NULL)
    {
       ll =  helper(root->left->left ,dp)  ;
       lr =   helper(root->left->right ,dp)  ;
    }  
    if(root->right != NULL)
    {
       rl =  helper(root->right->left , dp) ;
       rr = helper(root->right->right , dp) ;
    }
    int include = ll + lr + rr + rl + root->data ;
    int l = helper(root->left,dp) ;
    int r = helper(root->right,dp) ;
    return dp[root] = max(l + r , include) ;

}
int maximumSumOfNodes(TreeNode<int> *root)
{
	//    Write your code here
    //include 
    unordered_map < TreeNode<int> * , int > dp ; 
    return helper(root , dp) ;

}