> For the complete documentation index, see [llms.txt](https://ondrej-kvasnovsky-2.gitbook.io/algorithms/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ondrej-kvasnovsky-2.gitbook.io/algorithms/data-structures/binary-tree/serialize-and-deserialize-binary-tree-go-to-discuss.md).

# Serialize and Deserialize Binary Tree

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.

**Example:** 

```
You may serialize the following tree:

    1
   / \
  2   3
     / \
    4   5

as "[1,2,3,null,null,4,5]"
```

**Clarification:**The above format is the same as[how LeetCode serializes a binary tree](https://leetcode.com/faq/#binary-tree). You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.

**Note:** Do not use class member/global/static variables to store states. Your serialize and deserialize algorithms should be stateless.

## Solution

```
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Codec {

    // Encodes a tree to a single string.
    public String serialize(TreeNode root) {
        if (root == null) return null;
        // 0, 1, 2, 3, 4
        // 1, 2, 3, 4, 5
        // root             => 2 * 0 = 0
        // root.left        => 2 * 0 + 1 = 1
        // root.right       => 2 * 0 + 2 = 2
        // root.left.left   => 2 * 1 + 1 = 3
        // root.left.right  => 2 * 1 + 2 = 4
        // root.right.left  => 2 * 2 + 1 = 5
        // root.right.right => 2 * 2 + 2 = 6
        // read root, and append its value plus values of left and right
        // do the same for left and right
        // then the same for left.left and left.right
        StringBuilder sb = new StringBuilder();
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            TreeNode node = queue.poll();
            if (node == null) {
                sb.append("null,");
                continue;
            }
            sb.append(node.val);
            sb.append(",");
            queue.offer(node.left);
            queue.offer(node.right);
        }
        String result = sb.toString();
        System.out.println(result);
        return result.substring(0, result.length() - 1);
    }

    // Decodes your encoded data to tree.
    public TreeNode deserialize(String data) {
        if (data == null) return null;
        String[] split = data.split(",");
        Queue<TreeNode> queue = new LinkedList<>();
        TreeNode root = new TreeNode(Integer.valueOf(split[0]));
        queue.offer(root);
        int index = 1;
        while (!queue.isEmpty()) {
            TreeNode node = queue.poll();
            // add left
            String leftValue = split[index++];
            if (!"null".equals(leftValue)) {
                TreeNode left = new TreeNode(Integer.valueOf(leftValue));
                node.left = left;
                queue.offer(left);
            }

            // add right
            String rightValue = split[index++];
            if (!"null".equals(rightValue)) {
                TreeNode right = new TreeNode(Integer.valueOf(rightValue));
                node.right = right;
                queue.offer(right);
            }
        }


        return root;
    }
}

// Your Codec object will be instantiated and called as such:
// Codec codec = new Codec();
// codec.deserialize(codec.serialize(root));

// Your Codec object will be instantiated and called as such:
// Codec codec = new Codec();
// codec.deserialize(codec.serialize(root));
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://ondrej-kvasnovsky-2.gitbook.io/algorithms/data-structures/binary-tree/serialize-and-deserialize-binary-tree-go-to-discuss.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.