"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 class=\"example\">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] &l
"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":"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 */",
"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.",
"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++ 20 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 gnu11 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://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-10\\\" target=\\\"_blank\\\">C# 10 with .NET 6 runtime</a></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 5.3.0 version of <a href=\\\"https://github.com/datastructures-js/priority-queue/tree/fb4fdb984834421279aeb081df7af624d17c2a03\\\" target=\\\"_blank\\\">datastructures-js/priority-queue</a> and 4.2.1 version of <a href=\\\"https://githu
