GFG PTOD | 16 Feb | Serialize and deserialize a binary tree | Medium level | Tree

void pre(Node *root, vector<int> &ans) {
        if(!root) {
            ans.push_back(-1);
            return;
        }
        ans.push_back(root->data);
        pre(root->left, ans);
        pre(root->right, ans);
    }
    // Function to serialize a tree and return a list containing nodes of tree.
    vector<int> serialize(Node *root) {
        // Your code here
        vector<int> ans;
        pre(root, ans);
        return ans;
    }

    int i = 0;
    // Function to deserialize a list and construct the tree.
    Node *deSerialize(vector<int> &arr) {
        // Your code here
        int val = arr[i];
        i++;
        if(val == -1) return NULL;
        Node *tmp = new Node(val);
        tmp->left = deSerialize(arr);
        tmp->right = deSerialize(arr);
        return tmp;
    }