{ "data": { "question": { "questionId": "297", "questionFrontendId": "297", "boundTopicId": null, "title": "Serialize and Deserialize Binary Tree", "titleSlug": "serialize-and-deserialize-binary-tree", "content": "

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.

\n\n

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.

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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.

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Example 1:

\n\"\"\n
\nInput: root = [1,2,3,null,null,4,5]\nOutput: [1,2,3,null,null,4,5]\n
\n\n

Example 2:

\n\n
\nInput: root = []\nOutput: []\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Hard", "likes": 9708, "dislikes": 355, "isLiked": null, "similarQuestions": "[{\"title\": \"Encode and Decode Strings\", \"titleSlug\": \"encode-and-decode-strings\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Serialize and Deserialize BST\", \"titleSlug\": \"serialize-and-deserialize-bst\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Find Duplicate Subtrees\", \"titleSlug\": \"find-duplicate-subtrees\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Serialize and Deserialize N-ary Tree\", \"titleSlug\": \"serialize-and-deserialize-n-ary-tree\", \"difficulty\": \"Hard\", \"translatedTitle\": null}]", "exampleTestcases": "[1,2,3,null,null,4,5]\n[]", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "String", "slug": "string", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Tree", "slug": "tree", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Depth-First Search", "slug": "depth-first-search", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Breadth-First Search", "slug": "breadth-first-search", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Design", "slug": "design", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Binary Tree", "slug": "binary-tree", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n * int val;\n * TreeNode *left;\n * TreeNode *right;\n * TreeNode(int x) : val(x), left(NULL), right(NULL) {}\n * };\n */\nclass Codec {\npublic:\n\n // Encodes a tree to a single string.\n string serialize(TreeNode* root) {\n \n }\n\n // Decodes your encoded data to tree.\n TreeNode* deserialize(string data) {\n \n }\n};\n\n// Your Codec object will be instantiated and called as such:\n// Codec ser, deser;\n// TreeNode* ans = deser.deserialize(ser.serialize(root));", "__typename": "CodeSnippetNode" }, { "lang": "Java", "langSlug": "java", "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n * int val;\n * TreeNode left;\n * TreeNode right;\n * TreeNode(int x) { val = x; }\n * }\n */\npublic class Codec {\n\n // Encodes a tree to a single string.\n public String serialize(TreeNode root) {\n \n }\n\n // Decodes your encoded data to tree.\n public TreeNode deserialize(String data) {\n \n }\n}\n\n// Your Codec object will be instantiated and called as such:\n// Codec ser = new Codec();\n// Codec deser = new Codec();\n// TreeNode ans = deser.deserialize(ser.serialize(root));", "__typename": "CodeSnippetNode" }, { "lang": "Python", "langSlug": "python", "code": "# Definition for a binary tree node.\n# class TreeNode(object):\n# def __init__(self, x):\n# self.val = x\n# self.left = None\n# self.right = None\n\nclass Codec:\n\n def serialize(self, root):\n \"\"\"Encodes a tree to a single string.\n \n :type root: TreeNode\n :rtype: str\n \"\"\"\n \n\n def deserialize(self, data):\n \"\"\"Decodes your encoded data to tree.\n \n :type data: str\n :rtype: TreeNode\n \"\"\"\n \n\n# Your Codec object will be instantiated and called as such:\n# ser = Codec()\n# deser = Codec()\n# ans = deser.deserialize(ser.serialize(root))", "__typename": "CodeSnippetNode" }, { "lang": "Python3", "langSlug": "python3", "code": "# Definition for a binary tree node.\n# class TreeNode(object):\n# def __init__(self, x):\n# self.val = x\n# self.left = None\n# self.right = None\n\nclass Codec:\n\n def serialize(self, root):\n \"\"\"Encodes a tree to a single string.\n \n :type root: TreeNode\n :rtype: str\n \"\"\"\n \n\n def deserialize(self, data):\n \"\"\"Decodes your encoded data to tree.\n \n :type data: str\n :rtype: TreeNode\n \"\"\"\n \n\n# Your Codec object will be instantiated and called as such:\n# ser = Codec()\n# deser = Codec()\n# ans = deser.deserialize(ser.serialize(root))", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n * int val;\n * struct TreeNode *left;\n * struct TreeNode *right;\n * };\n */\n/** Encodes a tree to a single string. */\nchar* serialize(struct TreeNode* root) {\n \n}\n\n/** Decodes your encoded data to tree. */\nstruct TreeNode* deserialize(char* data) {\n \n}\n\n// Your functions will be called as such:\n// char* data = serialize(root);\n// deserialize(data);", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n * public int val;\n * public TreeNode left;\n * public TreeNode right;\n * public TreeNode(int x) { val = x; }\n * }\n */\npublic class Codec {\n\n // Encodes a tree to a single string.\n public string serialize(TreeNode root) {\n \n }\n\n // Decodes your encoded data to tree.\n public TreeNode deserialize(string data) {\n \n }\n}\n\n// Your Codec object will be instantiated and called as such:\n// Codec ser = new Codec();\n// Codec deser = new Codec();\n// TreeNode ans = deser.deserialize(ser.serialize(root));", "__typename": "CodeSnippetNode" }, { "lang": "JavaScript", "langSlug": "javascript", "code": "/**\n * Definition for a binary tree node.\n * function TreeNode(val) {\n * this.val = val;\n * this.left = this.right = null;\n * }\n */\n\n/**\n * Encodes a tree to a single string.\n *\n * @param {TreeNode} root\n * @return {string}\n */\nvar serialize = function(root) {\n \n};\n\n/**\n * Decodes your encoded data to tree.\n *\n * @param {string} data\n * @return {TreeNode}\n */\nvar deserialize = function(data) {\n \n};\n\n/**\n * Your functions will be called as such:\n * deserialize(serialize(root));\n */", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n * val: number\n * left: TreeNode | null\n * right: TreeNode | null\n * constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {\n * this.val = (val===undefined ? 0 : val)\n * this.left = (left===undefined ? null : left)\n * this.right = (right===undefined ? null : right)\n * }\n * }\n */\n\n/*\n * Encodes a tree to a single string.\n */\nfunction serialize(root: TreeNode | null): string {\n\n};\n\n/*\n * Decodes your encoded data to tree.\n */\nfunction deserialize(data: string): TreeNode | null {\n\n};\n\n\n/**\n * Your functions will be called as such:\n * deserialize(serialize(root));\n */", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n * public $val = null;\n * public $left = null;\n * public $right = null;\n * function __construct($value) { $this->val = $value; }\n * }\n */\n\nclass Codec {\n function __construct() {\n \n }\n \n /**\n * @param TreeNode $root\n * @return String\n */\n function serialize($root) {\n \n }\n \n /**\n * @param String $data\n * @return TreeNode\n */\n function deserialize($data) {\n \n }\n}\n\n/**\n * Your Codec object will be instantiated and called as such:\n * $ser = Codec();\n * $deser = Codec();\n * $data = $ser->serialize($root);\n * $ans = $deser->deserialize($data);\n */", "__typename": "CodeSnippetNode" }, { "lang": "Swift", "langSlug": "swift", "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n * public var val: Int\n * public var left: TreeNode?\n * public var right: TreeNode?\n * public init(_ val: Int) {\n * self.val = val\n * self.left = nil\n * self.right = nil\n * }\n * }\n */\n\nclass Codec {\n func serialize(_ root: TreeNode?) -> String {\n \n }\n \n func deserialize(_ data: String) -> TreeNode? {\n \n }\n}\n\n// Your Codec object will be instantiated and called as such:\n// var ser = Codec()\n// var deser = Codec()\n// deser.deserialize(ser.serialize(root))", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "/**\n * Definition for a binary tree node.\n * class TreeNode(var `val`: Int) {\n * var left: TreeNode? = null\n * var right: TreeNode? = null\n * }\n */\n\nclass Codec() {\n\t// Encodes a URL to a shortened URL.\n fun serialize(root: TreeNode?): String {\n \n }\n\n // Decodes your encoded data to tree.\n fun deserialize(data: String): TreeNode? {\n \n }\n}\n\n/**\n * Your Codec object will be instantiated and called as such:\n * var ser = Codec()\n * var deser = Codec()\n * var data = ser.serialize(longUrl)\n * var ans = deser.deserialize(data)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "/**\n * Definition for a binary tree node.\n * type TreeNode struct {\n * Val int\n * Left *TreeNode\n * Right *TreeNode\n * }\n */\n\ntype Codec struct {\n \n}\n\nfunc Constructor() Codec {\n \n}\n\n// Serializes a tree to a single string.\nfunc (this *Codec) serialize(root *TreeNode) string {\n \n}\n\n// Deserializes your encoded data to tree.\nfunc (this *Codec) deserialize(data string) *TreeNode { \n \n}\n\n\n/**\n * Your Codec object will be instantiated and called as such:\n * ser := Constructor();\n * deser := Constructor();\n * data := ser.serialize(root);\n * ans := deser.deserialize(data);\n */", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "# Definition for a binary tree node.\n# class TreeNode\n# attr_accessor :val, :left, :right\n# def initialize(val)\n# @val = val\n# @left, @right = nil, nil\n# end\n# end\n\n# Encodes a tree to a single string.\n#\n# @param {TreeNode} root\n# @return {string}\ndef serialize(root)\n \nend\n\n# Decodes your encoded data to tree.\n#\n# @param {string} data\n# @return {TreeNode}\ndef deserialize(data)\n \nend\n\n\n# Your functions will be called as such:\n# deserialize(serialize(data))", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "/**\n * Definition for a binary tree node.\n * class TreeNode(var _value: Int) {\n * var value: Int = _value\n * var left: TreeNode = null\n * var right: TreeNode = null\n * }\n */\n\nclass Codec {\n // Encodes a list of strings to a single string.\n def serialize(root: TreeNode): String = {\n \n }\n \n // Decodes a single string to a list of strings.\n def deserialize(data: String): TreeNode = {\n \n }\n}\n\n/**\n * Your Codec object will be instantiated and called as such:\n * var ser = new Codec()\n * var deser = new Codec()\n * val s = ser.serialize(root)\n * val ans = deser.deserialize(s)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "// Definition for a binary tree node.\n// #[derive(Debug, PartialEq, Eq)]\n// pub struct TreeNode {\n// pub val: i32,\n// pub left: Option>>,\n// pub right: Option>>,\n// }\n// \n// impl TreeNode {\n// #[inline]\n// pub fn new(val: i32) -> Self {\n// TreeNode {\n// val,\n// left: None,\n// right: None\n// }\n// }\n// }\nuse std::rc::Rc;\nuse std::cell::RefCell;\nstruct Codec {\n\t\n}\n\n/** \n * `&self` means the method takes an immutable reference.\n * If you need a mutable reference, change it to `&mut self` instead.\n */\nimpl Codec {\n fn new() -> Self {\n \n }\n\n fn serialize(&self, root: Option>>) -> String {\n \n }\n\t\n fn deserialize(&self, data: String) -> Option>> {\n \n }\n}\n\n/**\n * Your Codec object will be instantiated and called as such:\n * let obj = Codec::new();\n * let data: String = obj.serialize(strs);\n * let ans: Option>> = obj.deserialize(data);\n */", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"809.5K\", \"totalSubmission\": \"1.4M\", \"totalAcceptedRaw\": 809494, \"totalSubmissionRaw\": 1440838, \"acRate\": \"56.2%\"}", "hints": [], "solution": { "id": "563", "canSeeDetail": false, "paidOnly": true, "hasVideoSolution": false, "paidOnlyVideo": true, "__typename": "ArticleNode" }, "status": null, "sampleTestCase": "[1,2,3,null,null,4,5]", "metaData": "{\n \"name\": \"Codec\",\n \"params\": [\n {\n \"name\": \"root\",\n \"type\": \"TreeNode\"\n }\n ],\n \"return\": {\n \"type\": \"string\"\n },\n \"manual\": true\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

Compiled with clang 11 using the latest C++ 20 standard.

\\r\\n\\r\\n

Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\"], \"java\": [\"Java\", \"

OpenJDK 17. Java 8 features such as lambda expressions and stream API can be used.

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\\r\\n

Includes Pair class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.

\"], \"python\": [\"Python\", \"

Python 2.7.12.

\\r\\n\\r\\n

Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

\\r\\n\\r\\n

For Map/TreeMap data structure, you may use sortedcontainers library.

\\r\\n\\r\\n

Note that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.

\"], \"c\": [\"C\", \"

Compiled with gcc 8.2 using the gnu11 standard.

\\r\\n\\r\\n

Your code is compiled with level one optimization (-O1). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

\\r\\n\\r\\n

Most standard library headers are already included automatically for your convenience.

\\r\\n\\r\\n

For hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:

\\r\\n\\r\\n

1. Adding an item to a hash.\\r\\n

\\r\\nstruct hash_entry {\\r\\n    int id;            /* we'll use this field as the key */\\r\\n    char name[10];\\r\\n    UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n    HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n
\\r\\n

\\r\\n\\r\\n

2. Looking up an item in a hash:\\r\\n

\\r\\nstruct hash_entry *find_user(int user_id) {\\r\\n    struct hash_entry *s;\\r\\n    HASH_FIND_INT(users, &user_id, s);\\r\\n    return s;\\r\\n}\\r\\n
\\r\\n

\\r\\n\\r\\n

3. Deleting an item in a hash:\\r\\n

\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n    HASH_DEL(users, user);  \\r\\n}\\r\\n
\\r\\n

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C# 10 with .NET 6 runtime

\"], \"javascript\": [\"JavaScript\", \"

Node.js 16.13.2.

\\r\\n\\r\\n

Your code is run with --harmony flag, enabling new ES6 features.

\\r\\n\\r\\n

lodash.js library is included by default.

\\r\\n\\r\\n

For Priority Queue / Queue data structures, you may use 5.3.0 version of datastructures-js/priority-queue and 4.2.1 version of datastructures-js/queue.

\"], \"ruby\": [\"Ruby\", \"

Ruby 3.1

\\r\\n\\r\\n

Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms

\"], \"swift\": [\"Swift\", \"

Swift 5.5.2.

\"], \"golang\": [\"Go\", \"

Go 1.21

\\r\\n

Support https://godoc.org/github.com/emirpasic/gods@v1.18.1 library.

\"], \"python3\": [\"Python3\", \"

Python 3.10.

\\r\\n\\r\\n

Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

\\r\\n\\r\\n

For Map/TreeMap data structure, you may use sortedcontainers library.

\"], \"scala\": [\"Scala\", \"

Scala 2.13.7.

\"], \"kotlin\": [\"Kotlin\", \"

Kotlin 1.9.0.

\"], \"rust\": [\"Rust\", \"

Rust 1.58.1

\\r\\n\\r\\n

Supports rand v0.6\\u00a0from crates.io

\"], \"php\": [\"PHP\", \"

PHP 8.1.

\\r\\n

With bcmath module

\"], \"typescript\": [\"Typescript\", \"

TypeScript 5.1.6, Node.js 16.13.2.

\\r\\n\\r\\n

Your code is run with --harmony flag, enabling new ES2022 features.

\\r\\n\\r\\n

lodash.js library is included by default.

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