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297. Serialize and Deserialize Binary Tree
题目
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. You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.
Example 1:
Input: root = [1,2,3,null,null,4,5]
Output: [1,2,3,null,null,4,5]
Example 2:
Input: root = []
Output: []
Example 3:
Input: root = [1]
Output: [1]
Example 4:
Input: root = [1,2]
Output: [1,2]
Constraints:
- The number of nodes in the tree is in the range
[0, 104]. 1000 <= Node.val <= 1000
题目大意
设计一个算法，来序列化和反序列化二叉树。并不限制如何进行序列化和反序列化，但是你需要保证二叉树可以序列化为字符串，并且这个字符串可以被反序列化成原有的二叉树。
解题思路
-
- 将给定的二叉树想象成一颗满二叉树(不存在的结点用 null 填充)。
-
- 通过前序遍历，可以得到一个第一个结点为根的序列，然后递归进行序列化/反序列化即可。
代码
package leetcode
import (
"strconv"
"strings"
"github.com/halfrost/LeetCode-Go/structures"
)
type TreeNode = structures.TreeNode
type Codec struct {
builder strings.Builder
input []string
}
func Constructor() Codec {
return Codec{}
}
// Serializes a tree to a single string.
func (this *Codec) serialize(root *TreeNode) string {
if root == nil {
this.builder.WriteString("#,")
return ""
}
this.builder.WriteString(strconv.Itoa(root.Val) + ",")
this.serialize(root.Left)
this.serialize(root.Right)
return this.builder.String()
}
// Deserializes your encoded data to tree.
func (this *Codec) deserialize(data string) *TreeNode {
if len(data) == 0 {
return nil
}
this.input = strings.Split(data, ",")
return this.deserializeHelper()
}
func (this *Codec) deserializeHelper() *TreeNode {
if this.input[0] == "#" {
this.input = this.input[1:]
return nil
}
val, _ := strconv.Atoi(this.input[0])
this.input = this.input[1:]
return &TreeNode{
Val: val,
Left: this.deserializeHelper(),
Right: this.deserializeHelper(),
}
}
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