Design HashSet
<p>Design a HashSet without using any built-in hash table libraries.</p>

<p>Implement <code>MyHashSet</code> class:</p>

<ul>
	<li><code>void add(key)</code> Inserts the value <code>key</code> into the HashSet.</li>
	<li><code>bool contains(key)</code> Returns whether the value <code>key</code> exists in the HashSet or not.</li>
	<li><code>void remove(key)</code> Removes the value <code>key</code> in the HashSet. If <code>key</code> does not exist in the HashSet, do nothing.</li>
</ul>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input</strong>
[&quot;MyHashSet&quot;, &quot;add&quot;, &quot;add&quot;, &quot;contains&quot;, &quot;contains&quot;, &quot;add&quot;, &quot;contains&quot;, &quot;remove&quot;, &quot;contains&quot;]
[[], [1], [2], [1], [3], [2], [2], [2], [2]]
<strong>Output</strong>
[null, null, null, true, false, null, true, null, false]

<strong>Explanation</strong>
MyHashSet myHashSet = new MyHashSet();
myHashSet.add(1);      // set = [1]
myHashSet.add(2);      // set = [1, 2]
myHashSet.contains(1); // return True
myHashSet.contains(3); // return False, (not found)
myHashSet.add(2);      // set = [1, 2]
myHashSet.contains(2); // return True
myHashSet.remove(2);   // set = [1]
myHashSet.contains(2); // return False, (already removed)</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= key &lt;= 10<sup>6</sup></code></li>
	<li>At most <code>10<sup>4</sup></code> calls will be made to <code>add</code>, <code>remove</code>, and <code>contains</code>.</li>
</ul>

['design-hashmap', 'design-skiplist']
[]
[{"value": "cpp", "text": "C++", "defaultCode": "class MyHashSet {\npublic:\n    MyHashSet() {\n        \n    }\n    \n    void add(int key) {\n        \n    }\n    \n    void remove(int key) {\n        \n    }\n    \n    bool contains(int key) {\n        \n    }\n};\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * MyHashSet* obj = new MyHashSet();\n * obj->add(key);\n * obj->remove(key);\n * bool param_3 = obj->contains(key);\n */"}, {"value": "java", "text": "Java", "defaultCode": "class MyHashSet {\n\n    public MyHashSet() {\n        \n    }\n    \n    public void add(int key) {\n        \n    }\n    \n    public void remove(int key) {\n        \n    }\n    \n    public boolean contains(int key) {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * MyHashSet obj = new MyHashSet();\n * obj.add(key);\n * obj.remove(key);\n * boolean param_3 = obj.contains(key);\n */"}, {"value": "python", "text": "Python", "defaultCode": "class MyHashSet(object):\n\n    def __init__(self):\n        \n\n    def add(self, key):\n        \"\"\"\n        :type key: int\n        :rtype: None\n        \"\"\"\n        \n\n    def remove(self, key):\n        \"\"\"\n        :type key: int\n        :rtype: None\n        \"\"\"\n        \n\n    def contains(self, key):\n        \"\"\"\n        :type key: int\n        :rtype: bool\n        \"\"\"\n        \n\n\n# Your MyHashSet object will be instantiated and called as such:\n# obj = MyHashSet()\n# obj.add(key)\n# obj.remove(key)\n# param_3 = obj.contains(key)"}, {"value": "python3", "text": "Python3", "defaultCode": "class MyHashSet:\n\n    def __init__(self):\n        \n\n    def add(self, key: int) -> None:\n        \n\n    def remove(self, key: int) -> None:\n        \n\n    def contains(self, key: int) -> bool:\n        \n\n\n# Your MyHashSet object will be instantiated and called as such:\n# obj = MyHashSet()\n# obj.add(key)\n# obj.remove(key)\n# param_3 = obj.contains(key)"}, {"value": "c", "text": "C", "defaultCode": "\n\n\ntypedef struct {\n    \n} MyHashSet;\n\n\nMyHashSet* myHashSetCreate() {\n    \n}\n\nvoid myHashSetAdd(MyHashSet* obj, int key) {\n    \n}\n\nvoid myHashSetRemove(MyHashSet* obj, int key) {\n    \n}\n\nbool myHashSetContains(MyHashSet* obj, int key) {\n    \n}\n\nvoid myHashSetFree(MyHashSet* obj) {\n    \n}\n\n/**\n * Your MyHashSet struct will be instantiated and called as such:\n * MyHashSet* obj = myHashSetCreate();\n * myHashSetAdd(obj, key);\n \n * myHashSetRemove(obj, key);\n \n * bool param_3 = myHashSetContains(obj, key);\n \n * myHashSetFree(obj);\n*/"}, {"value": "csharp", "text": "C#", "defaultCode": "public class MyHashSet {\n\n    public MyHashSet() {\n        \n    }\n    \n    public void Add(int key) {\n        \n    }\n    \n    public void Remove(int key) {\n        \n    }\n    \n    public bool Contains(int key) {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * MyHashSet obj = new MyHashSet();\n * obj.Add(key);\n * obj.Remove(key);\n * bool param_3 = obj.Contains(key);\n */"}, {"value": "javascript", "text": "JavaScript", "defaultCode": "\nvar MyHashSet = function() {\n    \n};\n\n/** \n * @param {number} key\n * @return {void}\n */\nMyHashSet.prototype.add = function(key) {\n    \n};\n\n/** \n * @param {number} key\n * @return {void}\n */\nMyHashSet.prototype.remove = function(key) {\n    \n};\n\n/** \n * @param {number} key\n * @return {boolean}\n */\nMyHashSet.prototype.contains = function(key) {\n    \n};\n\n/** \n * Your MyHashSet object will be instantiated and called as such:\n * var obj = new MyHashSet()\n * obj.add(key)\n * obj.remove(key)\n * var param_3 = obj.contains(key)\n */"}, {"value": "typescript", "text": "TypeScript", "defaultCode": "class MyHashSet {\n    constructor() {\n        \n    }\n\n    add(key: number): void {\n        \n    }\n\n    remove(key: number): void {\n        \n    }\n\n    contains(key: number): boolean {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * var obj = new MyHashSet()\n * obj.add(key)\n * obj.remove(key)\n * var param_3 = obj.contains(key)\n */"}, {"value": "php", "text": "PHP", "defaultCode": "class MyHashSet {\n    /**\n     */\n    function __construct() {\n        \n    }\n  \n    /**\n     * @param Integer $key\n     * @return NULL\n     */\n    function add($key) {\n        \n    }\n  \n    /**\n     * @param Integer $key\n     * @return NULL\n     */\n    function remove($key) {\n        \n    }\n  \n    /**\n     * @param Integer $key\n     * @return Boolean\n     */\n    function contains($key) {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * $obj = MyHashSet();\n * $obj->add($key);\n * $obj->remove($key);\n * $ret_3 = $obj->contains($key);\n */"}, {"value": "swift", "text": "Swift", "defaultCode": "\nclass MyHashSet {\n\n    init() {\n        \n    }\n    \n    func add(_ key: Int) {\n        \n    }\n    \n    func remove(_ key: Int) {\n        \n    }\n    \n    func contains(_ key: Int) -> Bool {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * let obj = MyHashSet()\n * obj.add(key)\n * obj.remove(key)\n * let ret_3: Bool = obj.contains(key)\n */"}, {"value": "kotlin", "text": "Kotlin", "defaultCode": "class MyHashSet() {\n\n    fun add(key: Int) {\n        \n    }\n\n    fun remove(key: Int) {\n        \n    }\n\n    fun contains(key: Int): Boolean {\n        \n    }\n\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * var obj = MyHashSet()\n * obj.add(key)\n * obj.remove(key)\n * var param_3 = obj.contains(key)\n */"}, {"value": "dart", "text": "Dart", "defaultCode": "class MyHashSet {\n\n  MyHashSet() {\n    \n  }\n  \n  void add(int key) {\n    \n  }\n  \n  void remove(int key) {\n    \n  }\n  \n  bool contains(int key) {\n    \n  }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * MyHashSet obj = MyHashSet();\n * obj.add(key);\n * obj.remove(key);\n * bool param3 = obj.contains(key);\n */"}, {"value": "golang", "text": "Go", "defaultCode": "type MyHashSet struct {\n    \n}\n\n\nfunc Constructor() MyHashSet {\n    \n}\n\n\nfunc (this *MyHashSet) Add(key int)  {\n    \n}\n\n\nfunc (this *MyHashSet) Remove(key int)  {\n    \n}\n\n\nfunc (this *MyHashSet) Contains(key int) bool {\n    \n}\n\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * obj := Constructor();\n * obj.Add(key);\n * obj.Remove(key);\n * param_3 := obj.Contains(key);\n */"}, {"value": "ruby", "text": "Ruby", "defaultCode": "class MyHashSet\n    def initialize()\n        \n    end\n\n\n=begin\n    :type key: Integer\n    :rtype: Void\n=end\n    def add(key)\n        \n    end\n\n\n=begin\n    :type key: Integer\n    :rtype: Void\n=end\n    def remove(key)\n        \n    end\n\n\n=begin\n    :type key: Integer\n    :rtype: Boolean\n=end\n    def contains(key)\n        \n    end\n\n\nend\n\n# Your MyHashSet object will be instantiated and called as such:\n# obj = MyHashSet.new()\n# obj.add(key)\n# obj.remove(key)\n# param_3 = obj.contains(key)"}, {"value": "scala", "text": "Scala", "defaultCode": "class MyHashSet() {\n\n    def add(key: Int): Unit = {\n        \n    }\n\n    def remove(key: Int): Unit = {\n        \n    }\n\n    def contains(key: Int): Boolean = {\n        \n    }\n\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * val obj = new MyHashSet()\n * obj.add(key)\n * obj.remove(key)\n * val param_3 = obj.contains(key)\n */"}, {"value": "rust", "text": "Rust", "defaultCode": "struct MyHashSet {\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 MyHashSet {\n\n    fn new() -> Self {\n        \n    }\n    \n    fn add(&self, key: i32) {\n        \n    }\n    \n    fn remove(&self, key: i32) {\n        \n    }\n    \n    fn contains(&self, key: i32) -> bool {\n        \n    }\n}\n\n/**\n * Your MyHashSet object will be instantiated and called as such:\n * let obj = MyHashSet::new();\n * obj.add(key);\n * obj.remove(key);\n * let ret_3: bool = obj.contains(key);\n */"}, {"value": "racket", "text": "Racket", "defaultCode": "(define my-hash-set%\n  (class object%\n    (super-new)\n    \n    (init-field)\n    \n    ; add : exact-integer? -> void?\n    (define/public (add key)\n      )\n    ; remove : exact-integer? -> void?\n    (define/public (remove key)\n      )\n    ; contains : exact-integer? -> boolean?\n    (define/public (contains key)\n      )))\n\n;; Your my-hash-set% object will be instantiated and called as such:\n;; (define obj (new my-hash-set%))\n;; (send obj add key)\n;; (send obj remove key)\n;; (define param_3 (send obj contains key))"}, {"value": "erlang", "text": "Erlang", "defaultCode": "-spec my_hash_set_init_() -> any().\nmy_hash_set_init_() ->\n  .\n\n-spec my_hash_set_add(Key :: integer()) -> any().\nmy_hash_set_add(Key) ->\n  .\n\n-spec my_hash_set_remove(Key :: integer()) -> any().\nmy_hash_set_remove(Key) ->\n  .\n\n-spec my_hash_set_contains(Key :: integer()) -> boolean().\nmy_hash_set_contains(Key) ->\n  .\n\n\n%% Your functions will be called as such:\n%% my_hash_set_init_(),\n%% my_hash_set_add(Key),\n%% my_hash_set_remove(Key),\n%% Param_3 = my_hash_set_contains(Key),\n\n%% my_hash_set_init_ will be called before every test case, in which you can do some necessary initializations."}, {"value": "elixir", "text": "Elixir", "defaultCode": "defmodule MyHashSet do\n  @spec init_() :: any\n  def init_() do\n    \n  end\n\n  @spec add(key :: integer) :: any\n  def add(key) do\n    \n  end\n\n  @spec remove(key :: integer) :: any\n  def remove(key) do\n    \n  end\n\n  @spec contains(key :: integer) :: boolean\n  def contains(key) do\n    \n  end\nend\n\n# Your functions will be called as such:\n# MyHashSet.init_()\n# MyHashSet.add(key)\n# MyHashSet.remove(key)\n# param_3 = MyHashSet.contains(key)\n\n# MyHashSet.init_ will be called before every test case, in which you can do some necessary initializations."}]
{
  "classname": "MyHashSet",
  "constructor": {
    "params": []
  },
  "methods": [
    {
      "params": [
        {
          "type": "integer",
          "name": "key"
        }
      ],
      "name": "add",
      "return": {
        "type": "void"
      }
    },
    {
      "params": [
        {
          "type": "integer",
          "name": "key"
        }
      ],
      "return": {
        "type": "void"
      },
      "name": "remove"
    },
    {
      "params": [
        {
          "type": "integer",
          "name": "key"
        }
      ],
      "return": {
        "type": "boolean"
      },
      "name": "contains"
    }
  ],
  "return": {
    "type": "boolean"
  },
  "systemdesign": true
}
{"cpp": ["C++", "<p>Compiled with <code> clang 19 </code> using the latest C++ 23 standard, and <code>libstdc++</code> provided by GCC 14.</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 21</code>. Using compile arguments: <code>--enable-preview --release 21</code></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 2.7.18</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\">is not maintained anymore</a>. For the latest Python, please choose Python3 instead.</p>"], "c": ["C", "<p>Compiled with <code>gcc 14</code> using the gnu11 standard.</p>\r\n\r\n<p>Your code is compiled with level one 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>\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-13\" target=\"_blank\">C# 13</a> with .NET 9 runtime</p>"], "javascript": ["JavaScript", "<p><code>Node.js 22.14.0</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 6.3.2 version of <a href=\"https://github.com/datastructures-js/priority-queue/tree/v6.3.2\" target=\"_blank\">datastructures-js/priority-queue</a> and 4.2.3 version of <a href=\"https://github.com/datastructures-js/queue/tree/v4.2.3\" target=\"_blank\">datastructures-js/queue</a> and 1.0.4 version of <a href=\"https://github.com/datastructures-js/deque/tree/v1.0.4\" target=\"_blank\">datastructures-js/deque</a>.</p>"], "ruby": ["Ruby", "<p><code>Ruby 3.2</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 6.0</code>.</p>\r\n\r\n<p>You may use the following packages:<br/>\r\n<a href=\"https://github.com/apple/swift-algorithms/tree/1.2.0\" target=\"_blank\">swift-algorithms 1.2.0</a><br/>\r\n<a href=\"https://github.com/apple/swift-collections/tree/1.1.4\" target=\"_blank\">swift-collections 1.1.4</a><br/>\r\n<a href=\"https://github.com/apple/swift-numerics/tree/1.0.2\" target=\"_blank\">swift-numerics 1.0.2</a></p>"], "golang": ["Go", "<p><code>Go 1.23</code></p>\r\n<p>Support <a href=\"https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1\" target=\"_blank\">https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1</a> and <a href=\"https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha\" target=\"_blank\">https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha</a> library.</p>"], "python3": ["Python3", "<p><code>Python 3.11</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 3.3.1</code>.</p>"], "kotlin": ["Kotlin", "<p><code>Kotlin 2.1.10</code>.</p>"], "rust": ["Rust", "<p><code>Rust 1.85.0</code>. Your code will be compiled with <code>opt-level</code> 2.</p>\r\n\r\n<p>Supports <a href=\"https://crates.io/crates/rand\" target=\"_blank\">rand v0.8</a> and <a href=\"https://crates.io/crates/regex\" target=\"_blank\">regex\u00a0v1</a> and <a href=\"https://crates.io/crates/itertools\" target=\"_blank\">itertools\u00a0v0.14</a> from crates.io</p>"], "php": ["PHP", "<p><code>PHP 8.2</code>.</p>\r\n<p>With bcmath module</p>"], "typescript": ["Typescript", "<p><code>TypeScript 5.7.3, Node.js 22.14.0</code>.</p>\r\n\r\n<p>Compile Options: <code>--alwaysStrict --strictBindCallApply --strictFunctionTypes --target ES2024</code></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 6.3.2 version of <a href=\"https://github.com/datastructures-js/priority-queue/tree/v6.3.2\" target=\"_blank\">datastructures-js/priority-queue</a> and 4.2.3 version of <a href=\"https://github.com/datastructures-js/queue/tree/v4.2.3\" target=\"_blank\">datastructures-js/queue</a> and 1.0.4 version of <a href=\"https://github.com/datastructures-js/deque/tree/v1.0.4\" target=\"_blank\">datastructures-js/deque</a>.</p>"], "racket": ["Racket", "<p><a href=\"https://docs.racket-lang.org/guide/performance.html#%28tech._c%29\" target=\"_blank\">Racket CS</a> v8.15</p>\r\n\r\n<p>Using <code>#lang racket</code></p>\r\n\r\n<p>Required <code>data/gvector data/queue data/order data/heap</code> automatically for your convenience</p>"], "erlang": ["Erlang", "Erlang/OTP 26"], "elixir": ["Elixir", "Elixir 1.17 with Erlang/OTP 26"], "dart": ["Dart", "<p>Dart 3.2. You may use package <a href=\"https://pub.dev/packages/collection/versions/1.18.0\" target=\"_blank\">collection</a></p>\r\n\r\n<p>Your code will be run directly without compiling</p>"]}
['Array', 'Hash Table', 'Linked List', 'Design', 'Hash Function']