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"content": "<p>Design a stack-like data structure to push elements to the stack and pop the most frequent element from the stack.</p>\n\n<p>Implement the <code>FreqStack</code> class:</p>\n\n<ul>\n\t<li><code>FreqStack()</code> constructs an empty frequency stack.</li>\n\t<li><code>void push(int val)</code> pushes an integer <code>val</code> onto the top of the stack.</li>\n\t<li><code>int pop()</code> removes and returns the most frequent element in the stack.\n\t<ul>\n\t\t<li>If there is a tie for the most frequent element, the element closest to the stack's top is removed and returned.</li>\n\t</ul>\n\t</li>\n</ul>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input</strong>\n["FreqStack", "push", "push", "push", "push", "push", "push", "pop", "pop", "pop", "pop"]\n[[], [5], [7], [5], [7], [4], [5], [], [], [], []]\n<strong>Output</strong>\n[null, null, null, null, null, null, null, 5, 7, 5, 4]\n\n<strong>Explanation</strong>\nFreqStack freqStack = new FreqStack();\nfreqStack.push(5); // The stack is [5]\nfreqStack.push(7); // The stack is [5,7]\nfreqStack.push(5); // The stack is [5,7,5]\nfreqStack.push(7); // The stack is [5,7,5,7]\nfreqStack.push(4); // The stack is [5,7,5,7,4]\nfreqStack.push(5); // The stack is [5,7,5,7,4,5]\nfreqStack.pop(); // return 5, as 5 is the most frequent. The stack becomes [5,7,5,7,4].\nfreqStack.pop(); // return 7, as 5 and 7 is the most frequent, but 7 is closest to the top. The stack becomes [5,7,5,4].\nfreqStack.pop(); // return 5, as 5 is the most frequent. The stack becomes [5,7,4].\nfreqStack.pop(); // return 4, as 4, 5 and 7 is the most frequent, but 4 is closest to the top. The stack becomes [5,7].\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>0 <= val <= 10<sup>9</sup></code></li>\n\t<li>At most <code>2 * 10<sup>4</sup></code> calls will be made to <code>push</code> and <code>pop</code>.</li>\n\t<li>It is guaranteed that there will be at least one element in the stack before calling <code>pop</code>.</li>\n</ul>\n",
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"lang": "C++",
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"code": "class FreqStack {\npublic:\n FreqStack() {\n \n }\n \n void push(int val) {\n \n }\n \n int pop() {\n \n }\n};\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * FreqStack* obj = new FreqStack();\n * obj->push(val);\n * int param_2 = obj->pop();\n */",
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"code": "class FreqStack {\n\n public FreqStack() {\n \n }\n \n public void push(int val) {\n \n }\n \n public int pop() {\n \n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * FreqStack obj = new FreqStack();\n * obj.push(val);\n * int param_2 = obj.pop();\n */",
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"code": "class FreqStack(object):\n\n def __init__(self):\n \n\n def push(self, val):\n \"\"\"\n :type val: int\n :rtype: None\n \"\"\"\n \n\n def pop(self):\n \"\"\"\n :rtype: int\n \"\"\"\n \n\n\n# Your FreqStack object will be instantiated and called as such:\n# obj = FreqStack()\n# obj.push(val)\n# param_2 = obj.pop()",
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"code": "class FreqStack:\n\n def __init__(self):\n \n\n def push(self, val: int) -> None:\n \n\n def pop(self) -> int:\n \n\n\n# Your FreqStack object will be instantiated and called as such:\n# obj = FreqStack()\n# obj.push(val)\n# param_2 = obj.pop()",
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"lang": "C",
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"code": "\n\n\ntypedef struct {\n \n} FreqStack;\n\n\nFreqStack* freqStackCreate() {\n \n}\n\nvoid freqStackPush(FreqStack* obj, int val) {\n \n}\n\nint freqStackPop(FreqStack* obj) {\n \n}\n\nvoid freqStackFree(FreqStack* obj) {\n \n}\n\n/**\n * Your FreqStack struct will be instantiated and called as such:\n * FreqStack* obj = freqStackCreate();\n * freqStackPush(obj, val);\n \n * int param_2 = freqStackPop(obj);\n \n * freqStackFree(obj);\n*/",
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"lang": "C#",
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"code": "public class FreqStack {\n\n public FreqStack() {\n \n }\n \n public void Push(int val) {\n \n }\n \n public int Pop() {\n \n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * FreqStack obj = new FreqStack();\n * obj.Push(val);\n * int param_2 = obj.Pop();\n */",
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"code": "\nvar FreqStack = function() {\n \n};\n\n/** \n * @param {number} val\n * @return {void}\n */\nFreqStack.prototype.push = function(val) {\n \n};\n\n/**\n * @return {number}\n */\nFreqStack.prototype.pop = function() {\n \n};\n\n/** \n * Your FreqStack object will be instantiated and called as such:\n * var obj = new FreqStack()\n * obj.push(val)\n * var param_2 = obj.pop()\n */",
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"lang": "Ruby",
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"code": "class FreqStack\n def initialize()\n \n end\n\n\n=begin\n :type val: Integer\n :rtype: Void\n=end\n def push(val)\n \n end\n\n\n=begin\n :rtype: Integer\n=end\n def pop()\n \n end\n\n\nend\n\n# Your FreqStack object will be instantiated and called as such:\n# obj = FreqStack.new()\n# obj.push(val)\n# param_2 = obj.pop()",
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"lang": "Swift",
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"code": "\nclass FreqStack {\n\n init() {\n \n }\n \n func push(_ val: Int) {\n \n }\n \n func pop() -> Int {\n \n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * let obj = FreqStack()\n * obj.push(val)\n * let ret_2: Int = obj.pop()\n */",
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"lang": "Go",
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"code": "type FreqStack struct {\n \n}\n\n\nfunc Constructor() FreqStack {\n \n}\n\n\nfunc (this *FreqStack) Push(val int) {\n \n}\n\n\nfunc (this *FreqStack) Pop() int {\n \n}\n\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * obj := Constructor();\n * obj.Push(val);\n * param_2 := obj.Pop();\n */",
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"lang": "Scala",
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"code": "class FreqStack() {\n\n def push(`val`: Int) {\n \n }\n\n def pop(): Int = {\n \n }\n\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * var obj = new FreqStack()\n * obj.push(`val`)\n * var param_2 = obj.pop()\n */",
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"code": "class FreqStack() {\n\n fun push(`val`: Int) {\n \n }\n\n fun pop(): Int {\n \n }\n\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * var obj = FreqStack()\n * obj.push(`val`)\n * var param_2 = obj.pop()\n */",
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"code": "struct FreqStack {\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 FreqStack {\n\n fn new() -> Self {\n \n }\n \n fn push(&self, val: i32) {\n \n }\n \n fn pop(&self) -> i32 {\n \n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * let obj = FreqStack::new();\n * obj.push(val);\n * let ret_2: i32 = obj.pop();\n */",
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"lang": "PHP",
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"code": "class FreqStack {\n /**\n */\n function __construct() {\n \n }\n \n /**\n * @param Integer $val\n * @return NULL\n */\n function push($val) {\n \n }\n \n /**\n * @return Integer\n */\n function pop() {\n \n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * $obj = FreqStack();\n * $obj->push($val);\n * $ret_2 = $obj->pop();\n */",
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"lang": "TypeScript",
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"code": "class FreqStack {\n constructor() {\n\n }\n\n push(val: number): void {\n\n }\n\n pop(): number {\n\n }\n}\n\n/**\n * Your FreqStack object will be instantiated and called as such:\n * var obj = new FreqStack()\n * obj.push(val)\n * var param_2 = obj.pop()\n */",
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"lang": "Racket",
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"code": "(define freq-stack%\n (class object%\n (super-new)\n (init-field)\n \n ; push : exact-integer? -> void?\n (define/public (push val)\n\n )\n ; pop : -> exact-integer?\n (define/public (pop)\n\n )))\n\n;; Your freq-stack% object will be instantiated and called as such:\n;; (define obj (new freq-stack%))\n;; (send obj push val)\n;; (define param_2 (send obj pop))",
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"code": "-spec freq_stack_init_() -> any().\nfreq_stack_init_() ->\n .\n\n-spec freq_stack_push(Val :: integer()) -> any().\nfreq_stack_push(Val) ->\n .\n\n-spec freq_stack_pop() -> integer().\nfreq_stack_pop() ->\n .\n\n\n%% Your functions will be called as such:\n%% freq_stack_init_(),\n%% freq_stack_push(Val),\n%% Param_2 = freq_stack_pop(),\n\n%% freq_stack_init_ will be called before every test case, in which you can do some necessary initializations.",
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"code": "defmodule FreqStack do\n @spec init_() :: any\n def init_() do\n\n end\n\n @spec push(val :: integer) :: any\n def push(val) do\n\n end\n\n @spec pop() :: integer\n def pop() do\n\n end\nend\n\n# Your functions will be called as such:\n# FreqStack.init_()\n# FreqStack.push(val)\n# param_2 = FreqStack.pop()\n\n# FreqStack.init_ will be called before every test case, in which you can do some necessary initializations.",
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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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