{
"data": {
"question": {
"questionId": "2306",
"questionFrontendId": "2196",
"boundTopicId": null,
"title": "Create Binary Tree From Descriptions",
"titleSlug": "create-binary-tree-from-descriptions",
"content": "<p>You are given a 2D integer array <code>descriptions</code> where <code>descriptions[i] = [parent<sub>i</sub>, child<sub>i</sub>, isLeft<sub>i</sub>]</code> indicates that <code>parent<sub>i</sub></code> is the <strong>parent</strong> of <code>child<sub>i</sub></code> in a <strong>binary</strong> tree of <strong>unique</strong> values. Furthermore,</p>\n\n<ul>\n\t<li>If <code>isLeft<sub>i</sub> == 1</code>, then <code>child<sub>i</sub></code> is the left child of <code>parent<sub>i</sub></code>.</li>\n\t<li>If <code>isLeft<sub>i</sub> == 0</code>, then <code>child<sub>i</sub></code> is the right child of <code>parent<sub>i</sub></code>.</li>\n</ul>\n\n<p>Construct the binary tree described by <code>descriptions</code> and return <em>its <strong>root</strong></em>.</p>\n\n<p>The test cases will be generated such that the binary tree is <strong>valid</strong>.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2022/02/09/example1drawio.png\" style=\"width: 300px; height: 236px;\" />\n<pre>\n<strong>Input:</strong> descriptions = [[20,15,1],[20,17,0],[50,20,1],[50,80,0],[80,19,1]]\n<strong>Output:</strong> [50,20,80,15,17,19]\n<strong>Explanation:</strong> The root node is the node with value 50 since it has no parent.\nThe resulting binary tree is shown in the diagram.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2022/02/09/example2drawio.png\" style=\"width: 131px; height: 300px;\" />\n<pre>\n<strong>Input:</strong> descriptions = [[1,2,1],[2,3,0],[3,4,1]]\n<strong>Output:</strong> [1,2,null,null,3,4]\n<strong>Explanation:</strong> The root node is the node with value 1 since it has no parent.\nThe resulting binary tree is shown in the diagram.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= descriptions.length <= 10<sup>4</sup></code></li>\n\t<li><code>descriptions[i].length == 3</code></li>\n\t<li><code>1 <= parent<sub>i</sub>, child<sub>i</sub> <= 10<sup>5</sup></code></li>\n\t<li><code>0 <= isLeft<sub>i</sub> <= 1</code></li>\n\t<li>The binary tree described by <code>descriptions</code> is valid.</li>\n</ul>\n",
"translatedTitle": null,
"translatedContent": null,
"isPaidOnly": false,
"difficulty": "Medium",
"likes": 295,
"dislikes": 7,
"isLiked": null,
"similarQuestions": "[{\"title\": \"Convert Sorted List to Binary Search Tree\", \"titleSlug\": \"convert-sorted-list-to-binary-search-tree\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Number Of Ways To Reconstruct A Tree\", \"titleSlug\": \"number-of-ways-to-reconstruct-a-tree\", \"difficulty\": \"Hard\", \"translatedTitle\": null}]",
"exampleTestcases": "[[20,15,1],[20,17,0],[50,20,1],[50,80,0],[80,19,1]]\n[[1,2,1],[2,3,0],[3,4,1]]",
"categoryTitle": "Algorithms",
"contributors": [],
"topicTags": [
{
"name": "Array",
"slug": "array",
"translatedName": null,
"__typename": "TopicTagNode"
},
{
"name": "Hash Table",
"slug": "hash-table",
"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": "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() : val(0), left(nullptr), right(nullptr) {}\n * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}\n * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}\n * };\n */\nclass Solution {\npublic:\n TreeNode* createBinaryTree(vector<vector<int>>& descriptions) {\n \n }\n};",
"__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() {}\n * TreeNode(int val) { this.val = val; }\n * TreeNode(int val, TreeNode left, TreeNode right) {\n * this.val = val;\n * this.left = left;\n * this.right = right;\n * }\n * }\n */\nclass Solution {\n public TreeNode createBinaryTree(int[][] descriptions) {\n \n }\n}",
"__typename": "CodeSnippetNode"
},
{
"lang": "Python",
"langSlug": "python",
"code": "# Definition for a binary tree node.\n# class TreeNode(object):\n# def __init__(self, val=0, left=None, right=None):\n# self.val = val\n# self.left = left\n# self.right = right\nclass Solution(object):\n def createBinaryTree(self, descriptions):\n \"\"\"\n :type descriptions: List[List[int]]\n :rtype: Optional[TreeNode]\n \"\"\"\n ",
"__typename": "CodeSnippetNode"
},
{
"lang": "Python3",
"langSlug": "python3",
"code": "# Definition for a binary tree node.\n# class TreeNode:\n# def __init__(self, val=0, left=None, right=None):\n# self.val = val\n# self.left = left\n# self.right = right\nclass Solution:\n def createBinaryTree(self, descriptions: List[List[int]]) -> Optional[TreeNode]:\n ",
"__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\n\nstruct TreeNode* createBinaryTree(int** descriptions, int descriptionsSize, int* descriptionsColSize){\n\n}",
"__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 val=0, TreeNode left=null, TreeNode right=null) {\n * this.val = val;\n * this.left = left;\n * this.right = right;\n * }\n * }\n */\npublic class Solution {\n public TreeNode CreateBinaryTree(int[][] descriptions) {\n \n }\n}",
"__typename": "CodeSnippetNode"
},
{
"lang": "JavaScript",
"langSlug": "javascript",
"code": "/**\n * Definition for a binary tree node.\n * function TreeNode(val, left, right) {\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 * @param {number[][]} descriptions\n * @return {TreeNode}\n */\nvar createBinaryTree = function(descriptions) {\n \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 = 0, left = nil, right = nil)\n# @val = val\n# @left = left\n# @right = right\n# end\n# end\n# @param {Integer[][]} descriptions\n# @return {TreeNode}\ndef create_binary_tree(descriptions)\n \nend",
"__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() { self.val = 0; self.left = nil; self.right = nil; }\n * public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }\n * public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {\n * self.val = val\n * self.left = left\n * self.right = right\n * }\n * }\n */\nclass Solution {\n func createBinaryTree(_ descriptions: [[Int]]) -> TreeNode? {\n \n }\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 */\nfunc createBinaryTree(descriptions [][]int) *TreeNode {\n \n}",
"__typename": "CodeSnippetNode"
},
{
"lang": "Scala",
"langSlug": "scala",
"code": "/**\n * Definition for a binary tree node.\n * class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {\n * var value: Int = _value\n * var left: TreeNode = _left\n * var right: TreeNode = _right\n * }\n */\nobject Solution {\n def createBinaryTree(descriptions: Array[Array[Int]]): TreeNode = {\n \n }\n}",
"__typename": "CodeSnippetNode"
},
{
"lang": "Kotlin",
"langSlug": "kotlin",
"code": "/**\n * Example:\n * var ti = TreeNode(5)\n * var v = ti.`val`\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 */\nclass Solution {\n fun createBinaryTree(descriptions: Array<IntArray>): TreeNode? {\n \n }\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<Rc<RefCell<TreeNode>>>,\n// pub right: Option<Rc<RefCell<TreeNode>>>,\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;\nimpl Solution {\n pub fn create_binary_tree(descriptions: Vec<Vec<i32>>) -> Option<Rc<RefCell<TreeNode>>> {\n \n }\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 $right = null;\n * function __construct($val = 0, $left = null, $right = null) {\n * $this->val = $val;\n * $this->left = $left;\n * $this->right = $right;\n * }\n * }\n */\nclass Solution {\n\n /**\n * @param Integer[][] $descriptions\n * @return TreeNode\n */\n function createBinaryTree($descriptions) {\n \n }\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\nfunction createBinaryTree(descriptions: number[][]): TreeNode | null {\n\n};",
"__typename": "CodeSnippetNode"
},
{
"lang": "Racket",
"langSlug": "racket",
"code": "; Definition for a binary tree node.\n#|\n\n; val : integer?\n; left : (or/c tree-node? #f)\n; right : (or/c tree-node? #f)\n(struct tree-node\n (val left right) #:mutable #:transparent)\n\n; constructor\n(define (make-tree-node [val 0])\n (tree-node val #f #f))\n\n|#\n\n(define/contract (create-binary-tree descriptions)\n (-> (listof (listof exact-integer?)) (or/c tree-node? #f))\n\n )",
"__typename": "CodeSnippetNode"
},
{
"lang": "Erlang",
"langSlug": "erlang",
"code": "%% Definition for a binary tree node.\n%%\n%% -record(tree_node, {val = 0 :: integer(),\n%% left = null :: 'null' | #tree_node{},\n%% right = null :: 'null' | #tree_node{}}).\n\n-spec create_binary_tree(Descriptions :: [[integer()]]) -> #tree_node{} | null.\ncreate_binary_tree(Descriptions) ->\n .",
"__typename": "CodeSnippetNode"
},
{
"lang": "Elixir",
"langSlug": "elixir",
"code": "# Definition for a binary tree node.\n#\n# defmodule TreeNode do\n# @type t :: %__MODULE__{\n# val: integer,\n# left: TreeNode.t() | nil,\n# right: TreeNode.t() | nil\n# }\n# defstruct val: 0, left: nil, right: nil\n# end\n\ndefmodule Solution do\n @spec create_binary_tree(descriptions :: [[integer]]) :: TreeNode.t | nil\n def create_binary_tree(descriptions) do\n\n end\nend",
"__typename": "CodeSnippetNode"
}
],
"stats": "{\"totalAccepted\": \"12.8K\", \"totalSubmission\": \"18.3K\", \"totalAcceptedRaw\": 12783, \"totalSubmissionRaw\": 18254, \"acRate\": \"70.0%\"}",
"hints": [
"Could you represent and store the descriptions more efficiently?",
"Could you find the root node?",
"The node that is not a child in any of the descriptions is the root node."
],
"solution": null,
"status": null,
"sampleTestCase": "[[20,15,1],[20,17,0],[50,20,1],[50,80,0],[80,19,1]]",
"metaData": "{\n \"name\": \"createBinaryTree\",\n \"params\": [\n {\n \"name\": \"descriptions\",\n \"type\": \"integer[][]\"\n }\n ],\n \"return\": {\n \"type\": \"TreeNode\"\n }\n}",
"judgerAvailable": true,
"judgeType": "large",
"mysqlSchemas": [],
"enableRunCode": true,
"enableTestMode": false,
"enableDebugger": true,
"envInfo": "{\"cpp\": [\"C++\", \"<p>Compiled with <code> clang 11 </code> using the latest C++ 17 standard.</p>\\r\\n\\r\\n<p>Your code is compiled with level two optimization (<code>-O2</code>). <a href=\\\"https://github.com/google/sanitizers/wiki/AddressSanitizer\\\" target=\\\"_blank\\\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\"], \"java\": [\"Java\", \"<p><code> OpenJDK 17 </code>. Java 8 features such as lambda expressions and stream API can be used. </p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\\r\\n<p>Includes <code>Pair</code> class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.</p>\"], \"python\": [\"Python\", \"<p><code>Python 2.7.12</code>.</p>\\r\\n\\r\\n<p>Most libraries are already imported automatically for your convenience, such as <a href=\\\"https://docs.python.org/2/library/array.html\\\" target=\\\"_blank\\\">array</a>, <a href=\\\"https://docs.python.org/2/library/bisect.html\\\" target=\\\"_blank\\\">bisect</a>, <a href=\\\"https://docs.python.org/2/library/collections.html\\\" target=\\\"_blank\\\">collections</a>. If you need more libraries, you can import it yourself.</p>\\r\\n\\r\\n<p>For Map/TreeMap data structure, you may use <a href=\\\"http://www.grantjenks.com/docs/sortedcontainers/\\\" target=\\\"_blank\\\">sortedcontainers</a> library.</p>\\r\\n\\r\\n<p>Note that Python 2.7 <a href=\\\"https://www.python.org/dev/peps/pep-0373/\\\" target=\\\"_blank\\\">will not be maintained past 2020</a>. For the latest Python, please choose Python3 instead.</p>\"], \"c\": [\"C\", \"<p>Compiled with <code>gcc 8.2</code> using the gnu99 standard.</p>\\r\\n\\r\\n<p>Your code is compiled with level one optimization (<code>-O1</code>). <a href=\\\"https://github.com/google/sanitizers/wiki/AddressSanitizer\\\" target=\\\"_blank\\\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\\r\\n\\r\\n<p>For hash table operations, you may use <a href=\\\"https://troydhanson.github.io/uthash/\\\" target=\\\"_blank\\\">uthash</a>. \\\"uthash.h\\\" is included by default. Below are some examples:</p>\\r\\n\\r\\n<p><b>1. Adding an item to a hash.</b>\\r\\n<pre>\\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</pre>\\r\\n</p>\\r\\n\\r\\n<p><b>2. Looking up an item in a hash:</b>\\r\\n<pre>\\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</pre>\\r\\n</p>\\r\\n\\r\\n<p><b>3. Deleting an item in a hash:</b>\\r\\n<pre>\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n HASH_DEL(users, user); \\r\\n}\\r\\n</pre>\\r\\n</p>\"], \"csharp\": [\"C#\", \"<p><a href=\\\"https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-9\\\" target=\\\"_blank\\\">C# 10 with .NET 6 runtime</a></p>\\r\\n\\r\\n<p>Your code is compiled with debug flag enabled (<code>/debug</code>).</p>\"], \"javascript\": [\"JavaScript\", \"<p><code>Node.js 16.13.2</code>.</p>\\r\\n\\r\\n<p>Your code is run with <code>--harmony</code> flag, enabling <a href=\\\"http://node.green/\\\" target=\\\"_blank\\\">new ES6 features</a>.</p>\\r\\n\\r\\n<p><a href=\\\"https://lodash.com\\\" target=\\\"_blank\\\">lodash.js</a> library is included by default.</p>\\r\\n\\r\\n<p>For Priority Queue / Queue data structures, you may use <a href=\\\"https://github.com/datastructures-js/priority-queue\\\" target=\\\"_blank\\\">datastructures-js/priority-queue</a> and <a href=\\\"https://github.com/datastructures-js/queue\\\" target=\\\"_blank\\\">datastructures-js/queue</a>.</p>\"], \"ruby\": [\"Ruby\", \"<p><code>Ruby 3.1</code></p>\\r\\n\\r\\n<p>Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms</p>\"], \"swift\": [\"Swift\", \"<p><code>Swift 5.5.2</code>.</p>\"], \"golang\": [\"Go\", \"<p><code>Go 1.17.6</code>.</p>\\r\\n\\r\\n<p>Support <a href=\\\"https://godoc.org/github.com/emirpasic/gods\\\" target=\\\"_blank\\\">https://godoc.org/github.com/emirpasic/gods</a> library.</p>\"], \"python3\": [\"Python3\", \"<p><code>Python 3.10</code>.</p>\\r\\n\\r\\n<p>Most libraries are already imported automatically for your convenience, such as <a href=\\\"https://docs.python.org/3/library/array.html\\\" target=\\\"_blank\\\">array</a>, <a href=\\\"https://docs.python.org/3/library/bisect.html\\\" target=\\\"_blank\\\">bisect</a>, <a href=\\\"https://docs.python.org/3/library/collections.html\\\" target=\\\"_blank\\\">collections</a>. If you need more libraries, you can import it yourself.</p>\\r\\n\\r\\n<p>For Map/TreeMap data structure, you may use <a href=\\\"http://www.grantjenks.com/docs/sortedcontainers/\\\" target=\\\"_blank\\\">sortedcontainers</a> library.</p>\"], \"scala\": [\"Scala\", \"<p><code>Scala 2.13.7</code>.</p>\"], \"kotlin\": [\"Kotlin\", \"<p><code>Kotlin 1.3.10</code>.</p>\"], \"rust\": [\"Rust\", \"<p><code>Rust 1.58.1</code></p>\\r\\n\\r\\n<p>Supports <a href=\\\"https://crates.io/crates/rand\\\" target=\\\"_blank\\\">rand </a> v0.6\\u00a0from crates.io</p>\"], \"php\": [\"PHP\", \"<p><code>PHP 8.1</code>.</p>\\r\\n<p>With bcmath module</p>\"], \"typescript\": [\"Typescript\", \"<p><code>TypeScript 4.5.4, Node.js 16.13.2</code>.</p>\\r\\n\\r\\n<p>Your code is run with <code>--harmony</code> flag, enabling <a href=\\\"http://node.green/\\\" target=\\\"_blank\\\">new ES2020 features</a>.</p>\\r\\n\\r\\n<p><a href=\\\"https://lodash.com\\\" target=\\\"_blank\\\">lodash.js</a> library is included by default.</p>\"], \"racket\": [\"Racket\", \"<p>Run with <code>Racket 8.3</code>.</p>\"], \"erlang\": [\"Erlang\", \"Erlang/OTP 24.2\"], \"elixir\": [\"Elixir\", \"Elixir 1.13.0 with Erlang/OTP 24.2\"]}",
"libraryUrl": null,
"adminUrl": null,
"challengeQuestion": null,
"__typename": "QuestionNode"
}
}
}