Implement Queue using Stacks
<p>Implement a first in first out (FIFO) queue using only two stacks. The implemented queue should support all the functions of a normal queue (<code>push</code>, <code>peek</code>, <code>pop</code>, and <code>empty</code>).</p>

<p>Implement the <code>MyQueue</code> class:</p>

<ul>
	<li><code>void push(int x)</code> Pushes element x to the back of the queue.</li>
	<li><code>int pop()</code> Removes the element from the front of the queue and returns it.</li>
	<li><code>int peek()</code> Returns the element at the front of the queue.</li>
	<li><code>boolean empty()</code> Returns <code>true</code> if the queue is empty, <code>false</code> otherwise.</li>
</ul>

<p><strong>Notes:</strong></p>

<ul>
	<li>You must use <strong>only</strong> standard operations of a stack, which means only <code>push to top</code>, <code>peek/pop from top</code>, <code>size</code>, and <code>is empty</code> operations are valid.</li>
	<li>Depending on your language, the stack may not be supported natively. You may simulate a stack using a list or deque (double-ended queue) as long as you use only a stack&#39;s standard operations.</li>
</ul>

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

<pre>
<strong>Input</strong>
[&quot;MyQueue&quot;, &quot;push&quot;, &quot;push&quot;, &quot;peek&quot;, &quot;pop&quot;, &quot;empty&quot;]
[[], [1], [2], [], [], []]
<strong>Output</strong>
[null, null, null, 1, 1, false]

<strong>Explanation</strong>
MyQueue myQueue = new MyQueue();
myQueue.push(1); // queue is: [1]
myQueue.push(2); // queue is: [1, 2] (leftmost is front of the queue)
myQueue.peek(); // return 1
myQueue.pop(); // return 1, queue is [2]
myQueue.empty(); // return false
</pre>

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

<ul>
	<li><code>1 &lt;= x &lt;= 9</code></li>
	<li>At most <code>100</code>&nbsp;calls will be made to <code>push</code>, <code>pop</code>, <code>peek</code>, and <code>empty</code>.</li>
	<li>All the calls to <code>pop</code> and <code>peek</code> are valid.</li>
</ul>

<p>&nbsp;</p>
<p><strong>Follow-up:</strong> Can you implement the queue such that each operation is <strong><a href="https://en.wikipedia.org/wiki/Amortized_analysis" target="_blank">amortized</a></strong> <code>O(1)</code> time complexity? In other words, performing <code>n</code> operations will take overall <code>O(n)</code> time even if one of those operations may take longer.</p>

['implement-stack-using-queues']
[]
[{"value": "cpp", "text": "C++", "defaultCode": "class MyQueue {\npublic:\n    MyQueue() {\n        \n    }\n    \n    void push(int x) {\n        \n    }\n    \n    int pop() {\n        \n    }\n    \n    int peek() {\n        \n    }\n    \n    bool empty() {\n        \n    }\n};\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * MyQueue* obj = new MyQueue();\n * obj->push(x);\n * int param_2 = obj->pop();\n * int param_3 = obj->peek();\n * bool param_4 = obj->empty();\n */"}, {"value": "java", "text": "Java", "defaultCode": "class MyQueue {\n\n    public MyQueue() {\n        \n    }\n    \n    public void push(int x) {\n        \n    }\n    \n    public int pop() {\n        \n    }\n    \n    public int peek() {\n        \n    }\n    \n    public boolean empty() {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * MyQueue obj = new MyQueue();\n * obj.push(x);\n * int param_2 = obj.pop();\n * int param_3 = obj.peek();\n * boolean param_4 = obj.empty();\n */"}, {"value": "python", "text": "Python", "defaultCode": "class MyQueue(object):\n\n    def __init__(self):\n        \n\n    def push(self, x):\n        \"\"\"\n        :type x: int\n        :rtype: None\n        \"\"\"\n        \n\n    def pop(self):\n        \"\"\"\n        :rtype: int\n        \"\"\"\n        \n\n    def peek(self):\n        \"\"\"\n        :rtype: int\n        \"\"\"\n        \n\n    def empty(self):\n        \"\"\"\n        :rtype: bool\n        \"\"\"\n        \n\n\n# Your MyQueue object will be instantiated and called as such:\n# obj = MyQueue()\n# obj.push(x)\n# param_2 = obj.pop()\n# param_3 = obj.peek()\n# param_4 = obj.empty()"}, {"value": "python3", "text": "Python3", "defaultCode": "class MyQueue:\n\n    def __init__(self):\n        \n\n    def push(self, x: int) -> None:\n        \n\n    def pop(self) -> int:\n        \n\n    def peek(self) -> int:\n        \n\n    def empty(self) -> bool:\n        \n\n\n# Your MyQueue object will be instantiated and called as such:\n# obj = MyQueue()\n# obj.push(x)\n# param_2 = obj.pop()\n# param_3 = obj.peek()\n# param_4 = obj.empty()"}, {"value": "c", "text": "C", "defaultCode": "\n\n\ntypedef struct {\n    \n} MyQueue;\n\n\nMyQueue* myQueueCreate() {\n    \n}\n\nvoid myQueuePush(MyQueue* obj, int x) {\n    \n}\n\nint myQueuePop(MyQueue* obj) {\n    \n}\n\nint myQueuePeek(MyQueue* obj) {\n    \n}\n\nbool myQueueEmpty(MyQueue* obj) {\n    \n}\n\nvoid myQueueFree(MyQueue* obj) {\n    \n}\n\n/**\n * Your MyQueue struct will be instantiated and called as such:\n * MyQueue* obj = myQueueCreate();\n * myQueuePush(obj, x);\n \n * int param_2 = myQueuePop(obj);\n \n * int param_3 = myQueuePeek(obj);\n \n * bool param_4 = myQueueEmpty(obj);\n \n * myQueueFree(obj);\n*/"}, {"value": "csharp", "text": "C#", "defaultCode": "public class MyQueue {\n\n    public MyQueue() {\n        \n    }\n    \n    public void Push(int x) {\n        \n    }\n    \n    public int Pop() {\n        \n    }\n    \n    public int Peek() {\n        \n    }\n    \n    public bool Empty() {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * MyQueue obj = new MyQueue();\n * obj.Push(x);\n * int param_2 = obj.Pop();\n * int param_3 = obj.Peek();\n * bool param_4 = obj.Empty();\n */"}, {"value": "javascript", "text": "JavaScript", "defaultCode": "\nvar MyQueue = function() {\n    \n};\n\n/** \n * @param {number} x\n * @return {void}\n */\nMyQueue.prototype.push = function(x) {\n    \n};\n\n/**\n * @return {number}\n */\nMyQueue.prototype.pop = function() {\n    \n};\n\n/**\n * @return {number}\n */\nMyQueue.prototype.peek = function() {\n    \n};\n\n/**\n * @return {boolean}\n */\nMyQueue.prototype.empty = function() {\n    \n};\n\n/** \n * Your MyQueue object will be instantiated and called as such:\n * var obj = new MyQueue()\n * obj.push(x)\n * var param_2 = obj.pop()\n * var param_3 = obj.peek()\n * var param_4 = obj.empty()\n */"}, {"value": "typescript", "text": "TypeScript", "defaultCode": "class MyQueue {\n    constructor() {\n        \n    }\n\n    push(x: number): void {\n        \n    }\n\n    pop(): number {\n        \n    }\n\n    peek(): number {\n        \n    }\n\n    empty(): boolean {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * var obj = new MyQueue()\n * obj.push(x)\n * var param_2 = obj.pop()\n * var param_3 = obj.peek()\n * var param_4 = obj.empty()\n */"}, {"value": "php", "text": "PHP", "defaultCode": "class MyQueue {\n    /**\n     */\n    function __construct() {\n        \n    }\n  \n    /**\n     * @param Integer $x\n     * @return NULL\n     */\n    function push($x) {\n        \n    }\n  \n    /**\n     * @return Integer\n     */\n    function pop() {\n        \n    }\n  \n    /**\n     * @return Integer\n     */\n    function peek() {\n        \n    }\n  \n    /**\n     * @return Boolean\n     */\n    function empty() {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * $obj = MyQueue();\n * $obj->push($x);\n * $ret_2 = $obj->pop();\n * $ret_3 = $obj->peek();\n * $ret_4 = $obj->empty();\n */"}, {"value": "swift", "text": "Swift", "defaultCode": "\nclass MyQueue {\n\n    init() {\n        \n    }\n    \n    func push(_ x: Int) {\n        \n    }\n    \n    func pop() -> Int {\n        \n    }\n    \n    func peek() -> Int {\n        \n    }\n    \n    func empty() -> Bool {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * let obj = MyQueue()\n * obj.push(x)\n * let ret_2: Int = obj.pop()\n * let ret_3: Int = obj.peek()\n * let ret_4: Bool = obj.empty()\n */"}, {"value": "kotlin", "text": "Kotlin", "defaultCode": "class MyQueue() {\n\n    fun push(x: Int) {\n        \n    }\n\n    fun pop(): Int {\n        \n    }\n\n    fun peek(): Int {\n        \n    }\n\n    fun empty(): Boolean {\n        \n    }\n\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * var obj = MyQueue()\n * obj.push(x)\n * var param_2 = obj.pop()\n * var param_3 = obj.peek()\n * var param_4 = obj.empty()\n */"}, {"value": "dart", "text": "Dart", "defaultCode": "class MyQueue {\n\n  MyQueue() {\n    \n  }\n  \n  void push(int x) {\n    \n  }\n  \n  int pop() {\n    \n  }\n  \n  int peek() {\n    \n  }\n  \n  bool empty() {\n    \n  }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * MyQueue obj = MyQueue();\n * obj.push(x);\n * int param2 = obj.pop();\n * int param3 = obj.peek();\n * bool param4 = obj.empty();\n */"}, {"value": "golang", "text": "Go", "defaultCode": "type MyQueue struct {\n    \n}\n\n\nfunc Constructor() MyQueue {\n    \n}\n\n\nfunc (this *MyQueue) Push(x int)  {\n    \n}\n\n\nfunc (this *MyQueue) Pop() int {\n    \n}\n\n\nfunc (this *MyQueue) Peek() int {\n    \n}\n\n\nfunc (this *MyQueue) Empty() bool {\n    \n}\n\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * obj := Constructor();\n * obj.Push(x);\n * param_2 := obj.Pop();\n * param_3 := obj.Peek();\n * param_4 := obj.Empty();\n */"}, {"value": "ruby", "text": "Ruby", "defaultCode": "class MyQueue\n    def initialize()\n        \n    end\n\n\n=begin\n    :type x: Integer\n    :rtype: Void\n=end\n    def push(x)\n        \n    end\n\n\n=begin\n    :rtype: Integer\n=end\n    def pop()\n        \n    end\n\n\n=begin\n    :rtype: Integer\n=end\n    def peek()\n        \n    end\n\n\n=begin\n    :rtype: Boolean\n=end\n    def empty()\n        \n    end\n\n\nend\n\n# Your MyQueue object will be instantiated and called as such:\n# obj = MyQueue.new()\n# obj.push(x)\n# param_2 = obj.pop()\n# param_3 = obj.peek()\n# param_4 = obj.empty()"}, {"value": "scala", "text": "Scala", "defaultCode": "class MyQueue() {\n\n    def push(x: Int): Unit = {\n        \n    }\n\n    def pop(): Int = {\n        \n    }\n\n    def peek(): Int = {\n        \n    }\n\n    def empty(): Boolean = {\n        \n    }\n\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * val obj = new MyQueue()\n * obj.push(x)\n * val param_2 = obj.pop()\n * val param_3 = obj.peek()\n * val param_4 = obj.empty()\n */"}, {"value": "rust", "text": "Rust", "defaultCode": "struct MyQueue {\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 MyQueue {\n\n    fn new() -> Self {\n        \n    }\n    \n    fn push(&self, x: i32) {\n        \n    }\n    \n    fn pop(&self) -> i32 {\n        \n    }\n    \n    fn peek(&self) -> i32 {\n        \n    }\n    \n    fn empty(&self) -> bool {\n        \n    }\n}\n\n/**\n * Your MyQueue object will be instantiated and called as such:\n * let obj = MyQueue::new();\n * obj.push(x);\n * let ret_2: i32 = obj.pop();\n * let ret_3: i32 = obj.peek();\n * let ret_4: bool = obj.empty();\n */"}, {"value": "racket", "text": "Racket", "defaultCode": "(define my-queue%\n  (class object%\n    (super-new)\n    \n    (init-field)\n    \n    ; push : exact-integer? -> void?\n    (define/public (push x)\n      )\n    ; pop : -> exact-integer?\n    (define/public (pop)\n      )\n    ; peek : -> exact-integer?\n    (define/public (peek)\n      )\n    ; empty : -> boolean?\n    (define/public (empty)\n      )))\n\n;; Your my-queue% object will be instantiated and called as such:\n;; (define obj (new my-queue%))\n;; (send obj push x)\n;; (define param_2 (send obj pop))\n;; (define param_3 (send obj peek))\n;; (define param_4 (send obj empty))"}, {"value": "erlang", "text": "Erlang", "defaultCode": "-spec my_queue_init_() -> any().\nmy_queue_init_() ->\n  .\n\n-spec my_queue_push(X :: integer()) -> any().\nmy_queue_push(X) ->\n  .\n\n-spec my_queue_pop() -> integer().\nmy_queue_pop() ->\n  .\n\n-spec my_queue_peek() -> integer().\nmy_queue_peek() ->\n  .\n\n-spec my_queue_empty() -> boolean().\nmy_queue_empty() ->\n  .\n\n\n%% Your functions will be called as such:\n%% my_queue_init_(),\n%% my_queue_push(X),\n%% Param_2 = my_queue_pop(),\n%% Param_3 = my_queue_peek(),\n%% Param_4 = my_queue_empty(),\n\n%% my_queue_init_ will be called before every test case, in which you can do some necessary initializations."}, {"value": "elixir", "text": "Elixir", "defaultCode": "defmodule MyQueue do\n  @spec init_() :: any\n  def init_() do\n    \n  end\n\n  @spec push(x :: integer) :: any\n  def push(x) do\n    \n  end\n\n  @spec pop() :: integer\n  def pop() do\n    \n  end\n\n  @spec peek() :: integer\n  def peek() do\n    \n  end\n\n  @spec empty() :: boolean\n  def empty() do\n    \n  end\nend\n\n# Your functions will be called as such:\n# MyQueue.init_()\n# MyQueue.push(x)\n# param_2 = MyQueue.pop()\n# param_3 = MyQueue.peek()\n# param_4 = MyQueue.empty()\n\n# MyQueue.init_ will be called before every test case, in which you can do some necessary initializations."}]
{
  "classname": "MyQueue",
  "constructor": {
    "params": []
  },
  "methods": [
    {
      "params": [
        {
          "type": "integer",
          "name": "x"
        }
      ],
      "return": {
        "type": "void"
      },
      "name": "push"
    },
    {
      "params": [],
      "return": {
        "type": "integer"
      },
      "name": "pop"
    },
    {
      "params": [],
      "return": {
        "type": "integer"
      },
      "name": "peek"
    },
    {
      "params": [],
      "return": {
        "type": "boolean"
      },
      "name": "empty"
    }
  ],
  "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>"]}
['Stack', 'Design', 'Queue']