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            "title": "Smallest K-Length Subsequence With Occurrences of a Letter",
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            "content": "<p>You are given a string <code>s</code>, an integer <code>k</code>, a letter <code>letter</code>, and an integer <code>repetition</code>.</p>\n\n<p>Return <em>the <strong>lexicographically smallest</strong> subsequence of</em> <code>s</code><em> of length</em> <code>k</code> <em>that has the letter</em> <code>letter</code> <em>appear <strong>at least</strong></em> <code>repetition</code> <em>times</em>. The test cases are generated so that the <code>letter</code> appears in <code>s</code> <strong>at least</strong> <code>repetition</code> times.</p>\n\n<p>A <strong>subsequence</strong> is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.</p>\n\n<p>A string <code>a</code> is <strong>lexicographically smaller</strong> than a string <code>b</code> if in the first position where <code>a</code> and <code>b</code> differ, string <code>a</code> has a letter that appears earlier in the alphabet than the corresponding letter in <code>b</code>.</p>\n\n<p>&nbsp;</p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> s = &quot;leet&quot;, k = 3, letter = &quot;e&quot;, repetition = 1\n<strong>Output:</strong> &quot;eet&quot;\n<strong>Explanation:</strong> There are four subsequences of length 3 that have the letter &#39;e&#39; appear at least 1 time:\n- &quot;lee&quot; (from &quot;<strong><u>lee</u></strong>t&quot;)\n- &quot;let&quot; (from &quot;<strong><u>le</u></strong>e<u><strong>t</strong></u>&quot;)\n- &quot;let&quot; (from &quot;<u><strong>l</strong></u>e<u><strong>et</strong></u>&quot;)\n- &quot;eet&quot; (from &quot;l<u><strong>eet</strong></u>&quot;)\nThe lexicographically smallest subsequence among them is &quot;eet&quot;.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n<img alt=\"example-2\" src=\"https://assets.leetcode.com/uploads/2021/09/13/smallest-k-length-subsequence.png\" style=\"width: 339px; height: 67px;\" />\n<pre>\n<strong>Input:</strong> s = &quot;leetcode&quot;, k = 4, letter = &quot;e&quot;, repetition = 2\n<strong>Output:</strong> &quot;ecde&quot;\n<strong>Explanation:</strong> &quot;ecde&quot; is the lexicographically smallest subsequence of length 4 that has the letter &quot;e&quot; appear at least 2 times.\n</pre>\n\n<p><strong>Example 3:</strong></p>\n\n<pre>\n<strong>Input:</strong> s = &quot;bb&quot;, k = 2, letter = &quot;b&quot;, repetition = 2\n<strong>Output:</strong> &quot;bb&quot;\n<strong>Explanation:</strong> &quot;bb&quot; is the only subsequence of length 2 that has the letter &quot;b&quot; appear at least 2 times.\n</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 &lt;= repetition &lt;= k &lt;= s.length &lt;= 5 * 10<sup>4</sup></code></li>\n\t<li><code>s</code> consists of lowercase English letters.</li>\n\t<li><code>letter</code> is a lowercase English letter, and appears in <code>s</code> at least <code>repetition</code> times.</li>\n</ul>\n",
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            "exampleTestcases": "\"leet\"\n3\n\"e\"\n1\n\"leetcode\"\n4\n\"e\"\n2\n\"bb\"\n2\n\"b\"\n2",
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                    "name": "String",
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                    "code": "class Solution(object):\n    def smallestSubsequence(self, s, k, letter, repetition):\n        \"\"\"\n        :type s: str\n        :type k: int\n        :type letter: str\n        :type repetition: int\n        :rtype: str\n        \"\"\"\n        ",
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                    "code": "/**\n * @param {string} s\n * @param {number} k\n * @param {character} letter\n * @param {number} repetition\n * @return {string}\n */\nvar smallestSubsequence = function(s, k, letter, repetition) {\n    \n};",
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                    "code": "# @param {String} s\n# @param {Integer} k\n# @param {Character} letter\n# @param {Integer} repetition\n# @return {String}\ndef smallest_subsequence(s, k, letter, repetition)\n    \nend",
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                    "code": "impl Solution {\n    pub fn smallest_subsequence(s: String, k: i32, letter: char, repetition: i32) -> String {\n        \n    }\n}",
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            "hints": [
                "Use stack. For every character to be appended, decide how many character(s) from the stack needs to get popped based on the stack length and the count of the required character.",
                "Pop the extra characters out from the stack and return the characters in the stack (reversed)."
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