Serialize and Deserialize BST

Serialization is converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment.

Design an algorithm to serialize and deserialize a binary search tree. There is no restriction on how your serialization/deserialization algorithm should work. You need to ensure that a binary search tree can be serialized to a string, and this string can be deserialized to the original tree structure.

The encoded string should be as compact as possible.

 Input: root = [2,1,3]
Output: [2,1,3]
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Codec {
public:

    // Encodes a tree to a single string.
    string serialize(TreeNode* root) {
        if(root == NULL)
        {
            return("");
        }
        string s = "";
        queue<TreeNode*>q;
        q.push(root);
        while(q.size()>0)
        {
            TreeNode* m = q.front();
            q.pop();
            if(m == NULL)
            {
                s.append("#,");
            }
            else
            {
                 s.append(to_string(m->val)+",");
            }
            if(m!= NULL)
            {
                q.push(m->left);
                q.push(m->right);
            }
        }
        cout<<s<<endl;
        return(s);
        
        
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string data) {
        if(data.size()== 0)
        {
            return(NULL);
        }
        stringstream s(data);
        string str;
        queue<TreeNode*>q;
        getline(s,str,',');
        TreeNode* m = new TreeNode(stoi(str));
        q.push(m);
        while(q.size()>0)
        {
            
            TreeNode* n =q.front();
            q.pop();
            getline(s,str,',');
            if(str == "#")
             {
                n->left = NULL;
            }
            else
            {
               TreeNode* n1 = new TreeNode(stoi(str));
                n->left = n1;
                q.push(n1);
            }
            getline(s,str,',');
            if(str == "#")
            {
                n->right = NULL;
                
            }
            else
            {
                TreeNode* n2 = new TreeNode(stoi(str));
                n->right = n2;
                q.push(n2);
            }
        }
        return(m);
    }
};
            
            
// Codec* ser = new Codec();
// Codec* deser = new Codec();
// string tree = ser->serialize(root);
// TreeNode* ans = deser->deserialize(tree);
// return ans;