> For the complete documentation index, see [llms.txt](https://coding-9.gitbook.io/untitled/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://coding-9.gitbook.io/untitled/trees/binary-tree/hard/297.-serialize-and-deserialize-binary-tree.md).

# 297. Serialize and Deserialize Binary Tree

## Problem Statement

<br>

Serialization is the process of 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 tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.

**Clarification:** The input/output format is the same as [how LeetCode serializes a binary tree](https://support.leetcode.com/hc/en-us/articles/360011883654-What-does-1-null-2-3-mean-in-binary-tree-representation-). You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.

&#x20;

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/09/15/serdeser.jpg)

<pre><code><strong>Input: root = [1,2,3,null,null,4,5]
</strong><strong>Output: [1,2,3,null,null,4,5]
</strong></code></pre>

**Example 2:**

<pre><code><strong>Input: root = []
</strong><strong>Output: []
</strong></code></pre>

&#x20;

**Constraints:**

* The number of nodes in the tree is in the range `[0, 104]`.
* `-1000 <= Node.val <= 1000`

## Intuition

```
Approach:

We did by preorder
Root->left->right

Traversed like that

```

### Links

<https://leetcode.com/problems/serialize-and-deserialize-binary-tree/description/>

### Video Links

### Approach 1:

```
```

{% code title="C++" lineNumbers="true" %}

```cpp
class Codec {
public:
        // Encodes a tree to a single string.
    string serialize(TreeNode* root) {
        string result = "";
        preorderSerialize(root, result);
        cout<<result<<endl;
        return result;
    }

    // Decodes your encoded data to tree.
    TreeNode* deserialize(string data) {
        int index = 0;
        return preorderDeserialize(data, index);
    }
    
    // serialize the tree through preorder traversal
    // seperate the node value by ',', a NULL node is represented as '*'
    void preorderSerialize(TreeNode* node, string& result) {
        if (node == NULL) {
            result += "*,";
            return;
        }
        result += to_string(node->val) + ',';
        preorderSerialize(node->left, result);
        preorderSerialize(node->right, result);
    }
    
    // also deserialize the tree through preorder traversal
    TreeNode* preorderDeserialize(string& data, int& index) {
        if (data[index] == '*') {
            index += 2;
            return NULL;
        }
        // check if the value of the node is negative
        bool negative = false;
        if (data[index] == '-') {
            negative = true;
            index++;
        }
        int value = 0;
        while (data[index] != ',') {
            value = value * 10 + (data[index] - '0');
            index++;
        }
        if (negative) {
            value = -value;
        }
        TreeNode* node = new TreeNode(value);
        index++;
        node->left = preorderDeserialize(data, index);
        node->right = preorderDeserialize(data, index);
        return node;
    }
};
```

{% endcode %}

### Approach 2:

```
```

{% code title="C++" lineNumbers="true" %}

```cpp
```

{% endcode %}

### Approach 3:

```
```

{% code title="C++" lineNumbers="true" %}

```cpp
```

{% endcode %}

### Approach 4:

```
```

{% code title="C++" lineNumbers="true" %}

```cpp
```

{% endcode %}

### Similar Problems

###