Flatten Nested List Iterator
<p>You are given a nested list of integers <code>nestedList</code>. Each element is either an integer or a list whose elements may also be integers or other lists. Implement an iterator to flatten it.</p>

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

<ul>
	<li><code>NestedIterator(List&lt;NestedInteger&gt; nestedList)</code> Initializes the iterator with the nested list <code>nestedList</code>.</li>
	<li><code>int next()</code> Returns the next integer in the nested list.</li>
	<li><code>boolean hasNext()</code> Returns <code>true</code> if there are still some integers in the nested list and <code>false</code> otherwise.</li>
</ul>

<p>Your code will be tested with the following pseudocode:</p>

<pre>
initialize iterator with nestedList
res = []
while iterator.hasNext()
    append iterator.next() to the end of res
return res
</pre>

<p>If <code>res</code> matches the expected flattened list, then your code will be judged as correct.</p>

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

<pre>
<strong>Input:</strong> nestedList = [[1,1],2,[1,1]]
<strong>Output:</strong> [1,1,2,1,1]
<strong>Explanation:</strong> By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1,1,2,1,1].
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nestedList = [1,[4,[6]]]
<strong>Output:</strong> [1,4,6]
<strong>Explanation:</strong> By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1,4,6].
</pre>

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

<ul>
	<li><code>1 &lt;= nestedList.length &lt;= 500</code></li>
	<li>The values of the integers in the nested list is in the range <code>[-10<sup>6</sup>, 10<sup>6</sup>]</code>.</li>
</ul>

['flatten-2d-vector', 'zigzag-iterator', 'mini-parser', 'array-nesting']
[]
[{"value": "cpp", "text": "C++", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * class NestedInteger {\n *   public:\n *     // Return true if this NestedInteger holds a single integer, rather than a nested list.\n *     bool isInteger() const;\n *\n *     // Return the single integer that this NestedInteger holds, if it holds a single integer\n *     // The result is undefined if this NestedInteger holds a nested list\n *     int getInteger() const;\n *\n *     // Return the nested list that this NestedInteger holds, if it holds a nested list\n *     // The result is undefined if this NestedInteger holds a single integer\n *     const vector<NestedInteger> &getList() const;\n * };\n */\n\nclass NestedIterator {\npublic:\n    NestedIterator(vector<NestedInteger> &nestedList) {\n        \n    }\n    \n    int next() {\n        \n    }\n    \n    bool hasNext() {\n        \n    }\n};\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * NestedIterator i(nestedList);\n * while (i.hasNext()) cout << i.next();\n */"}, {"value": "java", "text": "Java", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * public interface NestedInteger {\n *\n *     // @return true if this NestedInteger holds a single integer, rather than a nested list.\n *     public boolean isInteger();\n *\n *     // @return the single integer that this NestedInteger holds, if it holds a single integer\n *     // Return null if this NestedInteger holds a nested list\n *     public Integer getInteger();\n *\n *     // @return the nested list that this NestedInteger holds, if it holds a nested list\n *     // Return empty list if this NestedInteger holds a single integer\n *     public List<NestedInteger> getList();\n * }\n */\npublic class NestedIterator implements Iterator<Integer> {\n\n    public NestedIterator(List<NestedInteger> nestedList) {\n        \n    }\n\n    @Override\n    public Integer next() {\n        \n    }\n\n    @Override\n    public boolean hasNext() {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * NestedIterator i = new NestedIterator(nestedList);\n * while (i.hasNext()) v[f()] = i.next();\n */"}, {"value": "python", "text": "Python", "defaultCode": "# \"\"\"\n# This is the interface that allows for creating nested lists.\n# You should not implement it, or speculate about its implementation\n# \"\"\"\n#class NestedInteger(object):\n#    def isInteger(self):\n#        \"\"\"\n#        @return True if this NestedInteger holds a single integer, rather than a nested list.\n#        :rtype bool\n#        \"\"\"\n#\n#    def getInteger(self):\n#        \"\"\"\n#        @return the single integer that this NestedInteger holds, if it holds a single integer\n#        Return None if this NestedInteger holds a nested list\n#        :rtype int\n#        \"\"\"\n#\n#    def getList(self):\n#        \"\"\"\n#        @return the nested list that this NestedInteger holds, if it holds a nested list\n#        Return None if this NestedInteger holds a single integer\n#        :rtype List[NestedInteger]\n#        \"\"\"\n\nclass NestedIterator(object):\n\n    def __init__(self, nestedList):\n        \"\"\"\n        Initialize your data structure here.\n        :type nestedList: List[NestedInteger]\n        \"\"\"\n        \n\n    def next(self):\n        \"\"\"\n        :rtype: int\n        \"\"\"\n        \n\n    def hasNext(self):\n        \"\"\"\n        :rtype: bool\n        \"\"\"\n        \n\n# Your NestedIterator object will be instantiated and called as such:\n# i, v = NestedIterator(nestedList), []\n# while i.hasNext(): v.append(i.next())"}, {"value": "python3", "text": "Python3", "defaultCode": "# \"\"\"\n# This is the interface that allows for creating nested lists.\n# You should not implement it, or speculate about its implementation\n# \"\"\"\n#class NestedInteger:\n#    def isInteger(self) -> bool:\n#        \"\"\"\n#        @return True if this NestedInteger holds a single integer, rather than a nested list.\n#        \"\"\"\n#\n#    def getInteger(self) -> int:\n#        \"\"\"\n#        @return the single integer that this NestedInteger holds, if it holds a single integer\n#        Return None if this NestedInteger holds a nested list\n#        \"\"\"\n#\n#    def getList(self) -> [NestedInteger]:\n#        \"\"\"\n#        @return the nested list that this NestedInteger holds, if it holds a nested list\n#        Return None if this NestedInteger holds a single integer\n#        \"\"\"\n\nclass NestedIterator:\n    def __init__(self, nestedList: [NestedInteger]):\n        \n    \n    def next(self) -> int:\n        \n    \n    def hasNext(self) -> bool:\n         \n\n# Your NestedIterator object will be instantiated and called as such:\n# i, v = NestedIterator(nestedList), []\n# while i.hasNext(): v.append(i.next())"}, {"value": "c", "text": "C", "defaultCode": "/**\n * *********************************************************************\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * *********************************************************************\n *\n * // Return true if this NestedInteger holds a single integer, rather than a nested list.\n * bool NestedIntegerIsInteger(struct NestedInteger *);\n *\n * // Return the single integer that this NestedInteger holds, if it holds a single integer\n * // The result is undefined if this NestedInteger holds a nested list\n * int NestedIntegerGetInteger(struct NestedInteger *);\n *\n * // Return the nested list that this NestedInteger holds, if it holds a nested list\n * // The result is undefined if this NestedInteger holds a single integer\n * struct NestedInteger **NestedIntegerGetList(struct NestedInteger *);\n *\n * // Return the nested list's size that this NestedInteger holds, if it holds a nested list\n * // The result is undefined if this NestedInteger holds a single integer\n * int NestedIntegerGetListSize(struct NestedInteger *);\n * };\n */\nstruct NestedIterator {\n    \n};\n\nstruct NestedIterator *nestedIterCreate(struct NestedInteger** nestedList, int nestedListSize) {\n    \n}\n\nbool nestedIterHasNext(struct NestedIterator *iter) {\n    \n}\n\nint nestedIterNext(struct NestedIterator *iter) {\n    \n}\n\n/** Deallocates memory previously allocated for the iterator */\nvoid nestedIterFree(struct NestedIterator *iter) {\n    \n}\n\n/**\n * Your NestedIterator will be called like this:\n * struct NestedIterator *i = nestedIterCreate(nestedList, nestedListSize);\n * while (nestedIterHasNext(i)) printf(\"%d\\n\", nestedIterNext(i));\n * nestedIterFree(i);\n */"}, {"value": "csharp", "text": "C#", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * interface NestedInteger {\n *\n *     // @return true if this NestedInteger holds a single integer, rather than a nested list.\n *     bool IsInteger();\n *\n *     // @return the single integer that this NestedInteger holds, if it holds a single integer\n *     // Return null if this NestedInteger holds a nested list\n *     int GetInteger();\n *\n *     // @return the nested list that this NestedInteger holds, if it holds a nested list\n *     // Return null if this NestedInteger holds a single integer\n *     IList<NestedInteger> GetList();\n * }\n */\npublic class NestedIterator {\n\n    public NestedIterator(IList<NestedInteger> nestedList) {\n        \n    }\n\n    public bool HasNext() {\n        \n    }\n\n    public int Next() {\n        \n    }\n}\n\n/**\n * Your NestedIterator will be called like this:\n * NestedIterator i = new NestedIterator(nestedList);\n * while (i.HasNext()) v[f()] = i.Next();\n */"}, {"value": "javascript", "text": "JavaScript", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * function NestedInteger() {\n *\n *     Return true if this NestedInteger holds a single integer, rather than a nested list.\n *     @return {boolean}\n *     this.isInteger = function() {\n *         ...\n *     };\n *\n *     Return the single integer that this NestedInteger holds, if it holds a single integer\n *     Return null if this NestedInteger holds a nested list\n *     @return {integer}\n *     this.getInteger = function() {\n *         ...\n *     };\n *\n *     Return the nested list that this NestedInteger holds, if it holds a nested list\n *     Return null if this NestedInteger holds a single integer\n *     @return {NestedInteger[]}\n *     this.getList = function() {\n *         ...\n *     };\n * };\n */\n/**\n * @constructor\n * @param {NestedInteger[]} nestedList\n */\nvar NestedIterator = function(nestedList) {\n    \n};\n\n\n/**\n * @this NestedIterator\n * @returns {boolean}\n */\nNestedIterator.prototype.hasNext = function() {\n    \n};\n\n/**\n * @this NestedIterator\n * @returns {integer}\n */\nNestedIterator.prototype.next = function() {\n    \n};\n\n/**\n * Your NestedIterator will be called like this:\n * var i = new NestedIterator(nestedList), a = [];\n * while (i.hasNext()) a.push(i.next());\n*/"}, {"value": "typescript", "text": "TypeScript", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * class NestedInteger {\n *     If value is provided, then it holds a single integer\n *     Otherwise it holds an empty nested list\n *     constructor(value?: number) {\n *         ...\n *     };\n *\n *     Return true if this NestedInteger holds a single integer, rather than a nested list.\n *     isInteger(): boolean {\n *         ...\n *     };\n *\n *     Return the single integer that this NestedInteger holds, if it holds a single integer\n *     Return null if this NestedInteger holds a nested list\n *     getInteger(): number | null {\n *         ...\n *     };\n *\n *     Set this NestedInteger to hold a single integer equal to value.\n *     setInteger(value: number) {\n *         ...\n *     };\n *\n *     Set this NestedInteger to hold a nested list and adds a nested integer elem to it.\n *     add(elem: NestedInteger) {\n *         ...\n *     };\n *\n *     Return the nested list that this NestedInteger holds,\n *     or an empty list if this NestedInteger holds a single integer\n *     getList(): NestedInteger[] {\n *         ...\n *     };\n * };\n */\n\nclass NestedIterator {\n    constructor(nestedList: NestedInteger[]) {\n\t\t\n    }\n\n    hasNext(): boolean {\n\t\t\n    }\n\n\tnext(): number {\n\t\t\n    }\n}\n\n/**\n * Your ParkingSystem object will be instantiated and called as such:\n * var obj = new NestedIterator(nestedList)\n * var a: number[] = []\n * while (obj.hasNext()) a.push(obj.next());\n */"}, {"value": "php", "text": "PHP", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * class NestedInteger {\n *\n *     // if value is not specified, initializes an empty list.\n *     // Otherwise initializes a single integer equal to value.\n *     function __construct($value = null)\n *\n *     // Return true if this NestedInteger holds a single integer, rather than a nested list.\n *     function isInteger() : bool\n *\n *     // Return the single integer that this NestedInteger holds, if it holds a single integer\n *     // The result is undefined if this NestedInteger holds a nested list\n *     function getInteger()\n *\n *     // Set this NestedInteger to hold a single integer.\n *     function setInteger($i) : void\n *\n *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.\n *     function add($ni) : void\n *\n *     // Return the nested list that this NestedInteger holds, if it holds a nested list\n *     // The result is undefined if this NestedInteger holds a single integer\n *     function getList() : array\n * }\n */\n\nclass NestedIterator {\n    /**\n     * @param NestedInteger[] $nestedList\n     */\n    function __construct($nestedList) {\n        \n    }\n    \n    /**\n     * @return Integer\n     */\n    function next() {\n        \n    }\n    \n    /**\n     * @return Boolean\n     */\n    function hasNext() {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * $obj = NestedIterator($nestedList);\n * $ret_1 = $obj->next();\n * $ret_2 = $obj->hasNext();\n */"}, {"value": "swift", "text": "Swift", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * class NestedInteger {\n *     // Return true if this NestedInteger holds a single integer, rather than a nested list.\n *     public func isInteger() -> Bool\n *\n *     // Return the single integer that this NestedInteger holds, if it holds a single integer\n *     // The result is undefined if this NestedInteger holds a nested list\n *     public func getInteger() -> Int\n *\n *     // Set this NestedInteger to hold a single integer.\n *     public func setInteger(value: Int)\n *\n *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.\n *     public func add(elem: NestedInteger)\n *\n *     // Return the nested list that this NestedInteger holds, if it holds a nested list\n *     // The result is undefined if this NestedInteger holds a single integer\n *     public func getList() -> [NestedInteger]\n * }\n */\n\nclass NestedIterator {\n\n    init(_ nestedList: [NestedInteger]) {\n        \n    }\n    \n    func next() -> Int {\n        \n    }\n    \n    func hasNext() -> Bool {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * let obj = NestedIterator(nestedList)\n * let ret_1: Int = obj.next()\n * let ret_2: Bool = obj.hasNext()\n */"}, {"value": "kotlin", "text": "Kotlin", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * class NestedInteger {\n *     // Constructor initializes an empty nested list.\n *     constructor()\n *\n *     // Constructor initializes a single integer.\n *     constructor(value: Int)\n *\n *     // @return true if this NestedInteger holds a single integer, rather than a nested list.\n *     fun isInteger(): Boolean\n *\n *     // @return the single integer that this NestedInteger holds, if it holds a single integer\n *     // Return null if this NestedInteger holds a nested list\n *     fun getInteger(): Int?\n *\n *     // Set this NestedInteger to hold a single integer.\n *     fun setInteger(value: Int): Unit\n *\n *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.\n *     fun add(ni: NestedInteger): Unit\n *\n *     // @return the nested list that this NestedInteger holds, if it holds a nested list\n *     // Return null if this NestedInteger holds a single integer\n *     fun getList(): List<NestedInteger>?\n * }\n */\n\nclass NestedIterator(nestedList: List<NestedInteger>) {\n    fun next(): Int {\n        \n    }\n    \n    fun hasNext(): Boolean {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * var obj = NestedIterator(nestedList)\n * var param_1 = obj.next()\n * var param_2 = obj.hasNext()\n */"}, {"value": "golang", "text": "Go", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * type NestedInteger struct {\n * }\n *\n * // Return true if this NestedInteger holds a single integer, rather than a nested list.\n * func (this NestedInteger) IsInteger() bool {}\n *\n * // Return the single integer that this NestedInteger holds, if it holds a single integer\n * // The result is undefined if this NestedInteger holds a nested list\n * // So before calling this method, you should have a check\n * func (this NestedInteger) GetInteger() int {}\n *\n * // Set this NestedInteger to hold a single integer.\n * func (n *NestedInteger) SetInteger(value int) {}\n *\n * // Set this NestedInteger to hold a nested list and adds a nested integer to it.\n * func (this *NestedInteger) Add(elem NestedInteger) {}\n *\n * // Return the nested list that this NestedInteger holds, if it holds a nested list\n * // The list length is zero if this NestedInteger holds a single integer\n * // You can access NestedInteger's List element directly if you want to modify it\n * func (this NestedInteger) GetList() []*NestedInteger {}\n */\n\ntype NestedIterator struct {\n    \n}\n\nfunc Constructor(nestedList []*NestedInteger) *NestedIterator {\n    \n}\n\nfunc (this *NestedIterator) Next() int {\n    \n}\n\nfunc (this *NestedIterator) HasNext() bool {\n    \n}"}, {"value": "ruby", "text": "Ruby", "defaultCode": "# This is the interface that allows for creating nested lists.\n# You should not implement it, or speculate about its implementation\n#\n#class NestedInteger\n#    def is_integer()\n#        \"\"\"\n#        Return true if this NestedInteger holds a single integer, rather than a nested list.\n#        @return {Boolean}\n#        \"\"\"\n#\n#    def get_integer()\n#        \"\"\"\n#        Return the single integer that this NestedInteger holds, if it holds a single integer\n#        Return nil if this NestedInteger holds a nested list\n#        @return {Integer}\n#        \"\"\"\n#\n#    def get_list()\n#        \"\"\"\n#        Return the nested list that this NestedInteger holds, if it holds a nested list\n#        Return nil if this NestedInteger holds a single integer\n#        @return {NestedInteger[]}\n#        \"\"\"\n\nclass NestedIterator\n    # @param {NestedInteger[]} nested_list\n    def initialize(nested_list)\n        \n    end\n\n    # @return {Boolean}\n    def has_next\n        \n    end\n\n    # @return {Integer}\n    def next\n        \n    end\nend\n\n# Your NestedIterator will be called like this:\n# i, v = NestedIterator.new(nested_list), []\n# while i.has_next()\n#    v << i.next\n# end"}, {"value": "scala", "text": "Scala", "defaultCode": "/**\n * // This is the interface that allows for creating nested lists.\n * // You should not implement it, or speculate about its implementation\n * trait NestedInteger {\n *\n *   // Return true if this NestedInteger holds a single integer, rather than a nested list.\n *   def isInteger: Boolean\n *\n *   // Return the single integer that this NestedInteger holds, if it holds a single integer.\n *   def getInteger: Int\n *\n *   // Set this NestedInteger to hold a single integer.\n *   def setInteger(i: Int): Unit\n *\n *   // Return the nested list that this NestedInteger holds, if it holds a nested list.\n *   def getList: Array[NestedInteger]\n *\n *   // Set this NestedInteger to hold a nested list and adds a nested integer to it.\n *   def add(ni: NestedInteger): Unit\n * }\n */\n\nclass NestedIterator(_nestedList: List[NestedInteger]) {\n    def next(): Int = {\n        \n    }\n    \n    def hasNext(): Boolean = {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * var obj = new NestedIterator(nestedList)\n * var param_1 = obj.next()\n * var param_2 = obj.hasNext()\n */"}, {"value": "rust", "text": "Rust", "defaultCode": "// #[derive(Debug, PartialEq, Eq)]\n// pub enum NestedInteger {\n//   Int(i32),\n//   List(Vec<NestedInteger>)\n// }\nstruct NestedIterator {\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 NestedIterator {\n\n    fn new(nestedList: Vec<NestedInteger>) -> Self {\n        \n    }\n    \n    fn next(&self) -> i32 {\n        \n    }\n    \n    fn has_next(&self) -> bool {\n        \n    }\n}\n\n/**\n * Your NestedIterator object will be instantiated and called as such:\n * let obj = NestedIterator::new(nestedList);\n * let ret_1: i32 = obj.next();\n * let ret_2: bool = obj.has_next();\n */"}]
{
  "name": "",
  "params": [
    {
      "name": "nestedList",
      "type": "list<NestedInteger>"
    }
  ],
  "return": {
    "type": "integer"
  },
  "manual": 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>"]}
['Stack', 'Tree', 'Depth-First Search', 'Design', 'Queue', 'Iterator']