"content":"<p>You are given a tree with <code>n</code> nodes numbered from <code>0</code> to <code>n - 1</code> in the form of a parent array <code>parent</code> where <code>parent[i]</code> is the parent of the <code>i<sup>th</sup></code> node. The root of the tree is node <code>0</code>, so <code>parent[0] = -1</code> since it has no parent. You want to design a data structure that allows users to lock, unlock, and upgrade nodes in the tree.</p>\n\n<p>The data structure should support the following functions:</p>\n\n<ul>\n\t<li><strong>Lock:</strong> <strong>Locks</strong> the given node for the given user and prevents other users from locking the same node. You may only lock a node using this function if the node is unlocked.</li>\n\t<li><strong>Unlock: Unlocks</strong> the given node for the given user. You may only unlock a node using this function if it is currently locked by the same user.</li>\n\t<li><b>Upgrade</b><strong>: Locks</strong> the given node for the given user and <strong>unlocks</strong> all of its descendants <strong>regardless</strong> of who locked it. You may only upgrade a node if <strong>all</strong> 3 conditions are true:\n\t<ul>\n\t\t<li>The node is unlocked,</li>\n\t\t<li>It has at least one locked descendant (by <strong>any</strong> user), and</li>\n\t\t<li>It does not have any locked ancestors.</li>\n\t</ul>\n\t</li>\n</ul>\n\n<p>Implement the <code>LockingTree</code> class:</p>\n\n<ul>\n\t<li><code>LockingTree(int[] parent)</code> initializes the data structure with the parent array.</li>\n\t<li><code>lock(int num, int user)</code> returns <code>true</code> if it is possible for the user with id <code>user</code> to lock the node <code>num</code>, or <code>false</code> otherwise. If it is possible, the node <code>num</code> will become<strong> locked</strong> by the user with id <code>user</code>.</li>\n\t<li><code>unlock(int num, int user)</code> returns <code>true</code> if it is possible for the user with id <code>user</code> to unlock the node <code>num</code>, or <code>false</code> otherwise. If it is possible, the node <code>num</code> will become <strong>unlocked</strong>.</li>\n\t<li><code>upgrade(int num, int user)</code> returns <code>true</code> if it is possible for the user with id <code>user</code> to upgrade the node <code>num</code>, or <code>false</code> otherwise. If it is possible, the node <code>num</code> will be <strong>upgraded</strong>.</li>\n</ul>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2021/07/29/untitled.png\" style=\"width: 375px; height: 246px;\"/>\n<pre>\n<strong>Input</strong>\n["LockingTree","lock","unlock","unlock","lock","upgrade","lock"]\n[[[-1,0,0,1,1,2,2]],[2,2],[2,3],[2,2],[4,5],[0,1],[0,1]]\n<strong>Output</strong>\n[null,true,false,true,true,true,false]\n\n<strong>Explanation</strong>\nLockingTreelockingTree=newLockingTree([-1,0,0,1,1,2,2]);\nlockingTree.lock(2,2);// return true because node 2 is unlocked.\n // Node 2 will now be locked by user 2.\nlockingTree.unlock(2, 3); // return false because user 3 cannot unlock a node locked by user 2.\nlockingTree.unlock(2, 2); // return true because node 2 was previously locked by user 2.\n // Node 2 will now be unlocked.\nlockingTree.lock(4, 5); // return true because node 4 is unlocked.\n // Node 4 will now be locked by user 5.\nlockingTree.upgrade(0, 1); // return true because node 0 is unlocked and has at least one locked descendant (node 4).\n // Node 0 will now be locked by user 1 and node 4 will now be unlocked.\nlockingTree.lock(0, 1); // return false because node 0 is already locked.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>n == parent.length</code></li>\n\t<li><code>2 <= n <= 2000</code></li>\n\t<li><code>0 <= parent[i] <= n - 1</code> f
"code":"class LockingTree:\n\n def __init__(self, parent: List[int]):\n \n\n def lock(self, num: int, user: int) -> bool:\n \n\n def unlock(self, num: int, user: int) -> bool:\n \n\n def upgrade(self, num: int, user: int) -> bool:\n \n\n\n# Your LockingTree object will be instantiated and called as such:\n# obj = LockingTree(parent)\n# param_1 = obj.lock(num,user)\n# param_2 = obj.unlock(num,user)\n# param_3 = obj.upgrade(num,user)",
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{
"lang":"C",
"langSlug":"c",
"code":"\n\n\ntypedef struct {\n \n} LockingTree;\n\n\nLockingTree* lockingTreeCreate(int* parent, int parentSize) {\n \n}\n\nbool lockingTreeLock(LockingTree* obj, int num, int user) {\n \n}\n\nbool lockingTreeUnlock(LockingTree* obj, int num, int user) {\n \n}\n\nbool lockingTreeUpgrade(LockingTree* obj, int num, int user) {\n \n}\n\nvoid lockingTreeFree(LockingTree* obj) {\n \n}\n\n/**\n * Your LockingTree struct will be instantiated and called as such:\n * LockingTree* obj = lockingTreeCreate(parent, parentSize);\n * bool param_1 = lockingTreeLock(obj, num, user);\n \n * bool param_2 = lockingTreeUnlock(obj, num, user);\n \n * bool param_3 = lockingTreeUpgrade(obj, num, user);\n \n * lockingTreeFree(obj);\n*/",
"__typename":"CodeSnippetNode"
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{
"lang":"C#",
"langSlug":"csharp",
"code":"public class LockingTree {\n\n public LockingTree(int[] parent) {\n \n }\n \n public bool Lock(int num, int user) {\n \n }\n \n public bool Unlock(int num, int user) {\n \n }\n \n public bool Upgrade(int num, int user) {\n \n }\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * LockingTree obj = new LockingTree(parent);\n * bool param_1 = obj.Lock(num,user);\n * bool param_2 = obj.Unlock(num,user);\n * bool param_3 = obj.Upgrade(num,user);\n */",
"__typename":"CodeSnippetNode"
},
{
"lang":"JavaScript",
"langSlug":"javascript",
"code":"/**\n * @param {number[]} parent\n */\nvar LockingTree = function(parent) {\n \n};\n\n/** \n * @param {number} num \n * @param {number} user\n * @return {boolean}\n */\nLockingTree.prototype.lock = function(num, user) {\n \n};\n\n/** \n * @param {number} num \n * @param {number} user\n * @return {boolean}\n */\nLockingTree.prototype.unlock = function(num, user) {\n \n};\n\n/** \n * @param {number} num \n * @param {number} user\n * @return {boolean}\n */\nLockingTree.prototype.upgrade = function(num, user) {\n \n};\n\n/** \n * Your LockingTree object will be instantiated and called as such:\n * var obj = new LockingTree(parent)\n * var param_1 = obj.lock(num,user)\n * var param_2 = obj.unlock(num,user)\n * var param_3 = obj.upgrade(num,user)\n */",
"code":"\nclass LockingTree {\n\n init(_ parent: [Int]) {\n \n }\n \n func lock(_ num: Int, _ user: Int) -> Bool {\n \n }\n \n func unlock(_ num: Int, _ user: Int) -> Bool {\n \n }\n \n func upgrade(_ num: Int, _ user: Int) -> Bool {\n \n }\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * let obj = LockingTree(parent)\n * let ret_1: Bool = obj.lock(num, user)\n * let ret_2: Bool = obj.unlock(num, user)\n * let ret_3: Bool = obj.upgrade(num, user)\n */",
"__typename":"CodeSnippetNode"
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{
"lang":"Go",
"langSlug":"golang",
"code":"type LockingTree struct {\n \n}\n\n\nfunc Constructor(parent []int) LockingTree {\n \n}\n\n\nfunc (this *LockingTree) Lock(num int, user int) bool {\n \n}\n\n\nfunc (this *LockingTree) Unlock(num int, user int) bool {\n \n}\n\n\nfunc (this *LockingTree) Upgrade(num int, user int) bool {\n \n}\n\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * obj := Constructor(parent);\n * param_1 := obj.Lock(num,user);\n * param_2 := obj.Unlock(num,user);\n * param_3 := obj.Upgrade(num,user);\n */",
"__typename":"CodeSnippetNode"
},
{
"lang":"Scala",
"langSlug":"scala",
"code":"class LockingTree(_parent: Array[Int]) {\n\n def lock(num: Int, user: Int): Boolean = {\n \n }\n\n def unlock(num: Int, user: Int): Boolean = {\n \n }\n\n def upgrade(num: Int, user: Int): Boolean = {\n \n }\n\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * var obj = new LockingTree(parent)\n * var param_1 = obj.lock(num,user)\n * var param_2 = obj.unlock(num,user)\n * var param_3 = obj.upgrade(num,user)\n */",
"__typename":"CodeSnippetNode"
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{
"lang":"Kotlin",
"langSlug":"kotlin",
"code":"class LockingTree(parent: IntArray) {\n\n fun lock(num: Int, user: Int): Boolean {\n \n }\n\n fun unlock(num: Int, user: Int): Boolean {\n \n }\n\n fun upgrade(num: Int, user: Int): Boolean {\n \n }\n\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * var obj = LockingTree(parent)\n * var param_1 = obj.lock(num,user)\n * var param_2 = obj.unlock(num,user)\n * var param_3 = obj.upgrade(num,user)\n */",
"__typename":"CodeSnippetNode"
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{
"lang":"Rust",
"langSlug":"rust",
"code":"struct LockingTree {\n\n}\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 LockingTree {\n\n fn new(parent: Vec<i32>) -> Self {\n \n }\n \n fn lock(&self, num: i32, user: i32) -> bool {\n \n }\n \n fn unlock(&self, num: i32, user: i32) -> bool {\n \n }\n \n fn upgrade(&self, num: i32, user: i32) -> bool {\n \n }\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * let obj = LockingTree::new(parent);\n * let ret_1: bool = obj.lock(num, user);\n * let ret_2: bool = obj.unlock(num, user);\n * let ret_3: bool = obj.upgrade(num, user);\n */",
"code":"class LockingTree {\n constructor(parent: number[]) {\n\n }\n\n lock(num: number, user: number): boolean {\n\n }\n\n unlock(num: number, user: number): boolean {\n\n }\n\n upgrade(num: number, user: number): boolean {\n\n }\n}\n\n/**\n * Your LockingTree object will be instantiated and called as such:\n * var obj = new LockingTree(parent)\n * var param_1 = obj.lock(num,user)\n * var param_2 = obj.unlock(num,user)\n * var param_3 = obj.upgrade(num,user)\n */",
"__typename":"CodeSnippetNode"
},
{
"lang":"Racket",
"langSlug":"racket",
"code":"(define locking-tree%\n (class object%\n (super-new)\n\n ; parent : (listof exact-integer?)\n (init-field\n parent)\n \n ; lock : exact-integer? exact-integer? -> boolean?\n (define/public (lock num user)\n\n )\n ; unlock : exact-integer? exact-integer? -> boolean?\n (define/public (unlock num user)\n\n )\n ; upgrade : exact-integer? exact-integer? -> boolean?\n (define/public (upgrade num user)\n\n )))\n\n;; Your locking-tree% object will be instantiated and called as such:\n;; (define obj (new locking-tree% [parent parent]))\n;; (define param_1 (send obj lock num user))\n;; (define param_2 (send obj unlock num user))\n;; (define param_3 (send obj upgrade num user))",
"__typename":"CodeSnippetNode"
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{
"lang":"Erlang",
"langSlug":"erlang",
"code":"-spec locking_tree_init_(Parent :: [integer()]) -> any().\nlocking_tree_init_(Parent) ->\n .\n\n-spec locking_tree_lock(Num :: integer(), User :: integer()) -> boolean().\nlocking_tree_lock(Num, User) ->\n .\n\n-spec locking_tree_unlock(Num :: integer(), User :: integer()) -> boolean().\nlocking_tree_unlock(Num, User) ->\n .\n\n-spec locking_tree_upgrade(Num :: integer(), User :: integer()) -> boolean().\nlocking_tree_upgrade(Num, User) ->\n .\n\n\n%% Your functions will be called as such:\n%% locking_tree_init_(Parent),\n%% Param_1 = locking_tree_lock(Num, User),\n%% Param_2 = locking_tree_unlock(Num, User),\n%% Param_3 = locking_tree_upgrade(Num, User),\n\n%% locking_tree_init_ will be called before every test case, in which you can do some necessary initializations.",
"__typename":"CodeSnippetNode"
},
{
"lang":"Elixir",
"langSlug":"elixir",
"code":"defmodule LockingTree do\n @spec init_(parent :: [integer]) :: any\n def init_(parent) do\n\n end\n\n @spec lock(num :: integer, user :: integer) :: boolean\n def lock(num, user) do\n\n end\n\n @spec unlock(num :: integer, user :: integer) :: boolean\n def unlock(num, user) do\n\n end\n\n @spec upgrade(num :: integer, user :: integer) :: boolean\n def upgrade(num, user) do\n\n end\nend\n\n# Your functions will be called as such:\n# LockingTree.init_(parent)\n# param_1 = LockingTree.lock(num, user)\n# param_2 = LockingTree.unlock(num, user)\n# param_3 = LockingTree.upgrade(num, user)\n\n# LockingTree.init_ will be called before every test case, in which you can do some necessary initializations.",
"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:
