Serialize and Deserialize Binary Tree
<p>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.</p>

<p>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.</p>

<p><strong>Clarification:</strong> The input/output format is the same as <a href="https://support.leetcode.com/hc/en-us/articles/32442719377939-How-to-create-test-cases-on-LeetCode#h_01J5EGREAW3NAEJ14XC07GRW1A" target="_blank">how LeetCode serializes a binary tree</a>. You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0200-0299/0297.Serialize%20and%20Deserialize%20Binary%20Tree/images/serdeser.jpg" style="width: 442px; height: 324px;" />
<pre>
<strong>Input:</strong> root = [1,2,3,null,null,4,5]
<strong>Output:</strong> [1,2,3,null,null,4,5]
</pre>

<p><strong class="example">Example 2:</strong></p>

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

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the tree is in the range <code>[0, 10<sup>4</sup>]</code>.</li>
	<li><code>-1000 &lt;= Node.val &lt;= 1000</code></li>
</ul>
Tree; Depth-First Search; Breadth-First Search; Design; String; Binary Tree
/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */

type Codec struct {
}

func Constructor() Codec {
	return Codec{}
}

// Serializes a tree to a single string.
func (this *Codec) serialize(root *TreeNode) string {
	if root == nil {
		return ""
	}
	q := []*TreeNode{root}
	ans := []string{}
	for len(q) > 0 {
		node := q[0]
		q = q[1:]
		if node != nil {
			ans = append(ans, strconv.Itoa(node.Val))
			q = append(q, node.Left)
			q = append(q, node.Right)
		} else {
			ans = append(ans, "#")
		}
	}
	return strings.Join(ans, ",")
}

// Deserializes your encoded data to tree.
func (this *Codec) deserialize(data string) *TreeNode {
	if data == "" {
		return nil
	}
	vals := strings.Split(data, ",")
	v, _ := strconv.Atoi(vals[0])
	i := 1
	root := &TreeNode{Val: v}
	q := []*TreeNode{root}
	for len(q) > 0 {
		node := q[0]
		q = q[1:]
		if x, err := strconv.Atoi(vals[i]); err == nil {
			node.Left = &TreeNode{Val: x}
			q = append(q, node.Left)
		}
		i++
		if x, err := strconv.Atoi(vals[i]); err == nil {
			node.Right = &TreeNode{Val: x}
			q = append(q, node.Right)
		}
		i++
	}
	return root
}

/**
 * Your Codec object will be instantiated and called as such:
 * ser := Constructor();
 * deser := Constructor();
 * data := ser.serialize(root);
 * ans := deser.deserialize(data);
 */