Serialize and Deserialize BST

Problem Description

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

The encoded string should be as compact as possible.

Example 1:

Input: root = [2,1,3]
Output: [2,1,3]

Example 2:

Input: root = []
Output: []

Constraints:

• The number of nodes in the tree is in the range [0, 104].
• 0 <= Node.val <= 104
• The input tree is guaranteed to be a binary search tree.

Solution (Go)

type Codec struct {
	cur *list.Element
}

func Constructor() Codec {
	return Codec{}
}

// Serializes a tree to a single string.
func (this *Codec) serialize(root *TreeNode) string {
	if root == nil {
		return ""
	}
	return fmt.Sprintf("%d,%s%s", root.Val, this.serialize(root.Left), this.serialize(root.Right))
}

// Deserializes your encoded data to tree.
func (this *Codec) deserialize(data string) *TreeNode {
	arr := strings.Split(data, ",")
	l := list.New()
	for _, v := range arr {
		if v != "" {
			l.PushBack(v)
		}
	}
	this.cur = l.Front()
	return this.deserializeList(0, math.MaxUint16)
}

// Deserializes your list to tree.
func (this *Codec) deserializeList(lower, upper int) *TreeNode {
	if this.cur == nil {
		return nil
	}
	valInt, _ := strconv.Atoi(this.cur.Value.(string))
	if valInt < lower || valInt > upper {
		return nil
	}
	node := &TreeNode{valInt, nil, nil}
	this.cur = this.cur.Next()
	node.Left = this.deserializeList(lower, valInt)
	node.Right = this.deserializeList(valInt, upper)
	return node
}