Serialize and Deserialize a Binary Tree

//{ Driver Code Starts
#include <bits/stdc++.h>

using namespace std;

// Tree Node
struct Node {
    int data;
    Node *left;
    Node *right;

    Node(int val) {
        data = val;
        left = right = NULL;
    }
};

// Function to Build Tree
Node *buildTree(string str) {
    // Corner Case
    if (str.length() == 0 || str[0] == 'N')
        return NULL;

    // Creating vector of strings from input
    // string after spliting by space
    vector<string> ip;

    istringstream iss(str);
    for (string str; iss >> str;)
        ip.push_back(str);

    // Create the root of the tree
    Node *root = new Node(stoi(ip[0]));

    // Push the root to the queue
    queue<Node *> queue;
    queue.push(root);

    // Starting from the second element
    int i = 1;
    while (!queue.empty() && i < ip.size()) {

        // Get and remove the front of the queue
        Node *currNode = queue.front();
        queue.pop();

        // Get the current Node's value from the string
        string currVal = ip[i];

        // If the left child is not null
        if (currVal != "N") {

            // Create the left child for the current Node
            currNode->left = new Node(stoi(currVal));

            // Push it to the queue
            queue.push(currNode->left);
        }

        // For the right child
        i++;
        if (i >= ip.size())
            break;
        currVal = ip[i];

        // If the right child is not null
        if (currVal != "N") {

            // Create the right child for the current Node
            currNode->right = new Node(stoi(currVal));

            // Push it to the queue
            queue.push(currNode->right);
        }
        i++;
    }

    return root;
}


// } Driver Code Ends
/* A binary tree node has data, pointer to left child
   and a pointer to right child
struct Node
{
    int data;
    Node* left;
    Node* right;
}; */


class Solution
{
    public:


    vector<int> serialize(Node *root)
    {
        //Your code here
        vector<int> ans;
        if(root==NULL)
        {
            return ans;
        }
         queue<Node*> q;
         q.push(root);
         while(!q.empty())
         {
             Node* node = q.front();
             q.pop();
             if(node==NULL)
             {
                 ans.push_back(-1);
             }
             else
             {
                 ans.push_back(node->data);
             }
             if(node!=NULL)
             {
                 q.push(node->left);
                 q.push(node->right);
             }
         }
        return ans;
    }

    //Function to deserialize a list and construct the tree.
    Node * deSerialize(vector<int> &A)
    {
      int index = 0;
      if(A.size()==index)
      {
          return NULL;
      }
      int val = A[index++];
      if(val==-1)
      {
          return NULL;
      }
      Node* root = new Node(val);
      queue<Node*> q;
      q.push(root);
      while(!q.empty())
      {
           Node* node = q.front();
           q.pop();
           val = A[index++];
           if(val==-1)
           {
               node->left=NULL;
           }
           else
           {
               Node* temp1 = new Node(val);
               node->left= temp1;
               q.push(temp1);
           }
           val = A[index++];
           if(val==-1)
           {
               node->right = NULL;
           }
           else
           {
                Node* temp2 = new Node(val);
               node->right= temp2;
               q.push(temp2);
           }
      }
      return root;

    }

};

//{ Driver Code Starts.

void inorder(Node *root) {
    if (root == NULL)
        return;
    inorder(root->left);
    cout << root->data << " ";
    inorder(root->right);
}

void _deleteTree(Node* node)
{
    if (node == NULL) return;

    /* first delete both subtrees */
    _deleteTree(node->left);
    _deleteTree(node->right);

    /* then delete the node */
    //cout << "Deleting node: " << node->data << endl;
    delete node;
}

/* Deletes a tree and sets the root as NULL */
void deleteTree(Node** node_ref)
{
    _deleteTree(*node_ref);
    *node_ref = NULL;
}

int main() {
    int tc;
    scanf("%d ", &tc);
    while (tc--) {
        string treeString;
        getline(cin, treeString);
        Node *root = buildTree(treeString);

        Solution serial, deserial;
        vector<int> A = serial.serialize(root);
        deleteTree(&root);
        Node *getRoot = deserial.deSerialize(A);
        inorder(getRoot);
        cout << "\n";

    }


    return 0;
}
// } Driver Code Ends