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"title": "Range Frequency Queries",
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"content": "<p>Design a data structure to find the <strong>frequency</strong> of a given value in a given subarray.</p>\n\n<p>The <strong>frequency</strong> of a value in a subarray is the number of occurrences of that value in the subarray.</p>\n\n<p>Implement the <code>RangeFreqQuery</code> class:</p>\n\n<ul>\n\t<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>\n\t<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>\n</ul>\n\n<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>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input</strong>\n["RangeFreqQuery", "query", "query"]\n[[[12, 33, 4, 56, 22, 2, 34, 33, 22, 12, 34, 56]], [1, 2, 4], [0, 11, 33]]\n<strong>Output</strong>\n[null, 1, 2]\n\n<strong>Explanation</strong>\nRangeFreqQuery rangeFreqQuery = new RangeFreqQuery([12, 33, 4, 56, 22, 2, 34, 33, 22, 12, 34, 56]);\nrangeFreqQuery.query(1, 2, 4); // return 1. The value 4 occurs 1 time in the subarray [33, 4]\nrangeFreqQuery.query(0, 11, 33); // return 2. The value 33 occurs 2 times in the whole array.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= arr.length <= 10<sup>5</sup></code></li>\n\t<li><code>1 <= arr[i], value <= 10<sup>4</sup></code></li>\n\t<li><code>0 <= left <= right < arr.length</code></li>\n\t<li>At most <code>10<sup>5</sup></code> calls will be made to <code>query</code></li>\n</ul>\n",
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"exampleTestcases": "[\"RangeFreqQuery\",\"query\",\"query\"]\n[[[12,33,4,56,22,2,34,33,22,12,34,56]],[1,2,4],[0,11,33]]",
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"lang": "C++",
"langSlug": "cpp",
"code": "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 */",
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"lang": "Java",
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"code": "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 */",
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"lang": "Python",
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"code": "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)",
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"code": "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)",
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"lang": "C",
"langSlug": "c",
"code": "\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*/",
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"lang": "C#",
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"code": "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 */",
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"lang": "JavaScript",
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"code": "/**\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 */",
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"lang": "Ruby",
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"code": "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)",
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"lang": "Swift",
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"code": "\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 */",
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"lang": "Go",
"langSlug": "golang",
"code": "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 */",
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"lang": "Scala",
"langSlug": "scala",
"code": "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 * var obj = new RangeFreqQuery(arr)\n * var param_1 = obj.query(left,right,value)\n */",
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"lang": "Kotlin",
"langSlug": "kotlin",
"code": "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 */",
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"lang": "Rust",
"langSlug": "rust",
"code": "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 */",
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"lang": "PHP",
"langSlug": "php",
"code": "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 */",
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"lang": "TypeScript",
"langSlug": "typescript",
"code": "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 */",
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"lang": "Racket",
"langSlug": "racket",
"code": "(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\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))",
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"lang": "Erlang",
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"code": "-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.",
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"lang": "Elixir",
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"code": "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.",
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"hints": [
"The queries must be answered efficiently to avoid time limit exceeded verdict.",
"Store the elements of the array in a data structure that helps answering the queries efficiently.",
"Use a hash table that stored for each value, the indices where that value appeared.",
"Use binary search over the indices of a value to find its range frequency."
],
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"sampleTestCase": "[\"RangeFreqQuery\",\"query\",\"query\"]\n[[[12,33,4,56,22,2,34,33,22,12,34,56]],[1,2,4],[0,11,33]]",
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For the latest Python, please choose Python3 instead.</p>\"], \"c\": [\"C\", \"<p>Compiled with <code>gcc 8.2</code> using the gnu99 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. 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