Distance between two nodes

 #include <map>
class Solution{
    public:
    /* Should return minimum distance between a and b
    in a tree with given root*/
   
Node * findNode(Node * root , int target )
    {
        if(root == NULL)
        {
            return NULL; 
        }
        if(root->data == target)
        {
            return root; 
        }
        Node *  a = findNode(root->right , target)  ; 
       Node * b = findNode(root->left , target )  ; 
        
        if(a == NULL)
        return b ; 
        else
        return a ; 
        
        
        
}
    int findDistanceBetweenNodes(Node *root, int node1, int node2)
{
    // Write your code here.
     map < Node * , Node * > parent ;
       queue < Node * > q ; 
       q.push(root) ; 
       while(!q.empty())
       {
           Node * f = q.front() ;
           q.pop() ;
           if(f->left != NULL)
           {
              q.push(f->left) ;
              parent[f->left] = f ; 
           }
           if(f->right != NULL)
           {
              q.push(f->right) ;
              parent[f->right] = f ; 
           }

       }
       //finding target node
       Node *  a =  findNode(root , node1) ;
       if(a == NULL)
       {
           return -1 ; 
       }
       Node *  b =  findNode(root , node2) ;
        if(b == NULL)
        return -1 ; 
       
   
       queue < Node * > qu ; 

       //finding nodes at distance k 
       qu.push(a) ;
       int t = 0 ; 
       map <Node *  , int> vis ;
       vis[a] = 1; 
       while(!qu.empty())
       {
            
            
             int siz = qu.size() ;
            
            
           for(int i = 0 ; i < siz ; i++) 
           {
                Node* f = qu.front() ;
             // cout << f->val << " " << siz << " " << t << endl ; 
                qu.pop() ;
                if(f->data == node2)
                {
                    
                    return t  ;  
                }
                if(f->left != NULL &&  vis.count(f->left) == 0)
                {
                 // cout << f->left->val << endl  ; 

                    qu.push(f->left) ;
                    vis[f->left] = 1 ; 
                }
                if(f->right != NULL  &&  vis.count(f->right) == 0)
                {
                   //  cout << f->right->val << " r" << endl  ; 

                    qu.push(f->right) ;
                    vis[f->right] = 1; 
                }
                if (parent[f] != NULL && vis.count(parent[f]) == 0 && f != root) {
                    // cout << parent[f] << endl ;
                     // cout << parent[f] << "r" << endl  ; 

                    qu.push(parent[f]);
                    vis[parent[f]] = 1;
                }
           }
          
           t = t + 1 ; 
             
       }
       return t - 1 ; 
}
    int findDist(Node* root, int a, int b) {
        // Your code here
        return  findDistanceBetweenNodes(root, a, b) ;
    }
};