Range Frequency Queries
<p>Design a data structure to find the <strong>frequency</strong> of a given value in a given subarray.</p>

<p>The <strong>frequency</strong> of a value in a subarray is the number of occurrences of that value in the subarray.</p>

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

<ul>
	<li><code>RangeFreqQuery(int[] arr)</code> Constructs an instance of the class with the given <strong>0-indexed</strong> integer array <code>arr</code>.</li>
	<li><code>int query(int left, int right, int value)</code> Returns the <strong>frequency</strong> of <code>value</code> in the subarray <code>arr[left...right]</code>.</li>
</ul>

<p>A <strong>subarray</strong> is a contiguous sequence of elements within an array. <code>arr[left...right]</code> denotes the subarray that contains the elements of <code>nums</code> between indices <code>left</code> and <code>right</code> (<strong>inclusive</strong>).</p>

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

<pre>
<strong>Input</strong>
[&quot;RangeFreqQuery&quot;, &quot;query&quot;, &quot;query&quot;]
[[[12, 33, 4, 56, 22, 2, 34, 33, 22, 12, 34, 56]], [1, 2, 4], [0, 11, 33]]
<strong>Output</strong>
[null, 1, 2]

<strong>Explanation</strong>
RangeFreqQuery rangeFreqQuery = new RangeFreqQuery([12, 33, 4, 56, 22, 2, 34, 33, 22, 12, 34, 56]);
rangeFreqQuery.query(1, 2, 4); // return 1. The value 4 occurs 1 time in the subarray [33, 4]
rangeFreqQuery.query(0, 11, 33); // return 2. The value 33 occurs 2 times in the whole array.
</pre>

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

<ul>
	<li><code>1 &lt;= arr.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= arr[i], value &lt;= 10<sup>4</sup></code></li>
	<li><code>0 &lt;= left &lt;= right &lt; arr.length</code></li>
	<li>At most <code>10<sup>5</sup></code> calls will be made to <code>query</code></li>
</ul>

[]
[]
[{"value": "cpp", "text": "C++", "defaultCode": "class RangeFreqQuery {\npublic:\n    RangeFreqQuery(vector<int>& arr) {\n        \n    }\n    \n    int query(int left, int right, int value) {\n        \n    }\n};\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * RangeFreqQuery* obj = new RangeFreqQuery(arr);\n * int param_1 = obj->query(left,right,value);\n */"}, {"value": "java", "text": "Java", "defaultCode": "class RangeFreqQuery {\n\n    public RangeFreqQuery(int[] arr) {\n        \n    }\n    \n    public int query(int left, int right, int value) {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * RangeFreqQuery obj = new RangeFreqQuery(arr);\n * int param_1 = obj.query(left,right,value);\n */"}, {"value": "python", "text": "Python", "defaultCode": "class RangeFreqQuery(object):\n\n    def __init__(self, arr):\n        \"\"\"\n        :type arr: List[int]\n        \"\"\"\n        \n\n    def query(self, left, right, value):\n        \"\"\"\n        :type left: int\n        :type right: int\n        :type value: int\n        :rtype: int\n        \"\"\"\n        \n\n\n# Your RangeFreqQuery object will be instantiated and called as such:\n# obj = RangeFreqQuery(arr)\n# param_1 = obj.query(left,right,value)"}, {"value": "python3", "text": "Python3", "defaultCode": "class RangeFreqQuery:\n\n    def __init__(self, arr: List[int]):\n        \n\n    def query(self, left: int, right: int, value: int) -> int:\n        \n\n\n# Your RangeFreqQuery object will be instantiated and called as such:\n# obj = RangeFreqQuery(arr)\n# param_1 = obj.query(left,right,value)"}, {"value": "c", "text": "C", "defaultCode": "\n\n\ntypedef struct {\n    \n} RangeFreqQuery;\n\n\nRangeFreqQuery* rangeFreqQueryCreate(int* arr, int arrSize) {\n    \n}\n\nint rangeFreqQueryQuery(RangeFreqQuery* obj, int left, int right, int value) {\n    \n}\n\nvoid rangeFreqQueryFree(RangeFreqQuery* obj) {\n    \n}\n\n/**\n * Your RangeFreqQuery struct will be instantiated and called as such:\n * RangeFreqQuery* obj = rangeFreqQueryCreate(arr, arrSize);\n * int param_1 = rangeFreqQueryQuery(obj, left, right, value);\n \n * rangeFreqQueryFree(obj);\n*/"}, {"value": "csharp", "text": "C#", "defaultCode": "public class RangeFreqQuery {\n\n    public RangeFreqQuery(int[] arr) {\n        \n    }\n    \n    public int Query(int left, int right, int value) {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * RangeFreqQuery obj = new RangeFreqQuery(arr);\n * int param_1 = obj.Query(left,right,value);\n */"}, {"value": "javascript", "text": "JavaScript", "defaultCode": "/**\n * @param {number[]} arr\n */\nvar RangeFreqQuery = function(arr) {\n    \n};\n\n/** \n * @param {number} left \n * @param {number} right \n * @param {number} value\n * @return {number}\n */\nRangeFreqQuery.prototype.query = function(left, right, value) {\n    \n};\n\n/** \n * Your RangeFreqQuery object will be instantiated and called as such:\n * var obj = new RangeFreqQuery(arr)\n * var param_1 = obj.query(left,right,value)\n */"}, {"value": "typescript", "text": "TypeScript", "defaultCode": "class RangeFreqQuery {\n    constructor(arr: number[]) {\n        \n    }\n\n    query(left: number, right: number, value: number): number {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * var obj = new RangeFreqQuery(arr)\n * var param_1 = obj.query(left,right,value)\n */"}, {"value": "php", "text": "PHP", "defaultCode": "class RangeFreqQuery {\n    /**\n     * @param Integer[] $arr\n     */\n    function __construct($arr) {\n        \n    }\n  \n    /**\n     * @param Integer $left\n     * @param Integer $right\n     * @param Integer $value\n     * @return Integer\n     */\n    function query($left, $right, $value) {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * $obj = RangeFreqQuery($arr);\n * $ret_1 = $obj->query($left, $right, $value);\n */"}, {"value": "swift", "text": "Swift", "defaultCode": "\nclass RangeFreqQuery {\n\n    init(_ arr: [Int]) {\n        \n    }\n    \n    func query(_ left: Int, _ right: Int, _ value: Int) -> Int {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * let obj = RangeFreqQuery(arr)\n * let ret_1: Int = obj.query(left, right, value)\n */"}, {"value": "kotlin", "text": "Kotlin", "defaultCode": "class RangeFreqQuery(arr: IntArray) {\n\n    fun query(left: Int, right: Int, value: Int): Int {\n        \n    }\n\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * var obj = RangeFreqQuery(arr)\n * var param_1 = obj.query(left,right,value)\n */"}, {"value": "dart", "text": "Dart", "defaultCode": "class RangeFreqQuery {\n\n  RangeFreqQuery(List<int> arr) {\n    \n  }\n  \n  int query(int left, int right, int value) {\n    \n  }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * RangeFreqQuery obj = RangeFreqQuery(arr);\n * int param1 = obj.query(left,right,value);\n */"}, {"value": "golang", "text": "Go", "defaultCode": "type RangeFreqQuery struct {\n    \n}\n\n\nfunc Constructor(arr []int) RangeFreqQuery {\n    \n}\n\n\nfunc (this *RangeFreqQuery) Query(left int, right int, value int) int {\n    \n}\n\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * obj := Constructor(arr);\n * param_1 := obj.Query(left,right,value);\n */"}, {"value": "ruby", "text": "Ruby", "defaultCode": "class RangeFreqQuery\n\n=begin\n    :type arr: Integer[]\n=end\n    def initialize(arr)\n        \n    end\n\n\n=begin\n    :type left: Integer\n    :type right: Integer\n    :type value: Integer\n    :rtype: Integer\n=end\n    def query(left, right, value)\n        \n    end\n\n\nend\n\n# Your RangeFreqQuery object will be instantiated and called as such:\n# obj = RangeFreqQuery.new(arr)\n# param_1 = obj.query(left, right, value)"}, {"value": "scala", "text": "Scala", "defaultCode": "class RangeFreqQuery(_arr: Array[Int]) {\n\n    def query(left: Int, right: Int, value: Int): Int = {\n        \n    }\n\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * val obj = new RangeFreqQuery(arr)\n * val param_1 = obj.query(left,right,value)\n */"}, {"value": "rust", "text": "Rust", "defaultCode": "struct RangeFreqQuery {\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 RangeFreqQuery {\n\n    fn new(arr: Vec<i32>) -> Self {\n        \n    }\n    \n    fn query(&self, left: i32, right: i32, value: i32) -> i32 {\n        \n    }\n}\n\n/**\n * Your RangeFreqQuery object will be instantiated and called as such:\n * let obj = RangeFreqQuery::new(arr);\n * let ret_1: i32 = obj.query(left, right, value);\n */"}, {"value": "racket", "text": "Racket", "defaultCode": "(define range-freq-query%\n  (class object%\n    (super-new)\n    \n    ; arr : (listof exact-integer?)\n    (init-field\n      arr)\n    \n    ; query : exact-integer? exact-integer? exact-integer? -> exact-integer?\n    (define/public (query left right value)\n      )))\n\n;; Your range-freq-query% object will be instantiated and called as such:\n;; (define obj (new range-freq-query% [arr arr]))\n;; (define param_1 (send obj query left right value))"}, {"value": "erlang", "text": "Erlang", "defaultCode": "-spec range_freq_query_init_(Arr :: [integer()]) -> any().\nrange_freq_query_init_(Arr) ->\n  .\n\n-spec range_freq_query_query(Left :: integer(), Right :: integer(), Value :: integer()) -> integer().\nrange_freq_query_query(Left, Right, Value) ->\n  .\n\n\n%% Your functions will be called as such:\n%% range_freq_query_init_(Arr),\n%% Param_1 = range_freq_query_query(Left, Right, Value),\n\n%% range_freq_query_init_ will be called before every test case, in which you can do some necessary initializations."}, {"value": "elixir", "text": "Elixir", "defaultCode": "defmodule RangeFreqQuery do\n  @spec init_(arr :: [integer]) :: any\n  def init_(arr) do\n    \n  end\n\n  @spec query(left :: integer, right :: integer, value :: integer) :: integer\n  def query(left, right, value) do\n    \n  end\nend\n\n# Your functions will be called as such:\n# RangeFreqQuery.init_(arr)\n# param_1 = RangeFreqQuery.query(left, right, value)\n\n# RangeFreqQuery.init_ will be called before every test case, in which you can do some necessary initializations."}]
{
  "classname": "RangeFreqQuery",
  "constructor": {
    "params": [
      {
        "type": "integer[]",
        "name": "arr"
      }
    ]
  },
  "methods": [
    {
      "params": [
        {
          "type": "integer",
          "name": "left"
        },
        {
          "type": "integer",
          "name": "right"
        },
        {
          "type": "integer",
          "name": "value"
        }
      ],
      "name": "query",
      "return": {
        "type": "integer"
      }
    }
  ],
  "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', 'Binary Search', 'Design', 'Segment Tree']