{ "data": { "question": { "questionId": "2140", "questionFrontendId": "2014", "boundTopicId": null, "title": "Longest Subsequence Repeated k Times", "titleSlug": "longest-subsequence-repeated-k-times", "content": "

You are given a string s of length n, and an integer k. You are tasked to find the longest subsequence repeated k times in string s.

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A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.

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A subsequence seq is repeated k times in the string s if seq * k is a subsequence of s, where seq * k represents a string constructed by concatenating seq k times.

\n\n\n\n

Return the longest subsequence repeated k times in string s. If multiple such subsequences are found, return the lexicographically largest one. If there is no such subsequence, return an empty string.

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Example 1:

\n\"example\n
\nInput: s = "letsleetcode", k = 2\nOutput: "let"\nExplanation: There are two longest subsequences repeated 2 times: "let" and "ete".\n"let" is the lexicographically largest one.\n
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Example 2:

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\nInput: s = "bb", k = 2\nOutput: "b"\nExplanation: The longest subsequence repeated 2 times is "b".\n
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Example 3:

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\nInput: s = "ab", k = 2\nOutput: ""\nExplanation: There is no subsequence repeated 2 times. Empty string is returned.\n
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Constraints:

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Do you know why?", "Find the characters that could be included in the potential answer. A character occurring more than or equal to k times can be used in the answer up to (count of the character / k) times.", "Try all possible candidates in reverse lexicographic order, and check the string for the subsequence condition." ], "solution": null, "status": null, "sampleTestCase": "\"letsleetcode\"\n2", "metaData": "{\n \"name\": \"longestSubsequenceRepeatedK\",\n \"params\": [\n {\n \"name\": \"s\",\n \"type\": \"string\"\n },\n {\n \"type\": \"integer\",\n \"name\": \"k\"\n }\n ],\n \"return\": {\n \"type\": \"string\"\n }\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "enableTestMode": false, "enableDebugger": true, "envInfo": "{\"cpp\": [\"C++\", \"

Compiled with clang 11 using the latest C++ 17 standard.

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Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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Most standard library headers are already included automatically for your convenience.

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OpenJDK 17 . Java 8 features such as lambda expressions and stream API can be used.

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Most standard library headers are already included automatically for your convenience.

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Python 2.7.12.

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Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

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For Map/TreeMap data structure, you may use sortedcontainers library.

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Note that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.

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Your code is compiled with level one optimization (-O1). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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Most standard library headers are already included automatically for your convenience.

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For hash table operations, you may use uthash. \\\"uthash.h\\\" is included by default. Below are some examples:

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3. Deleting an item in a hash:\\r\\n

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\\r\\n

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C# 10 with .NET 6 runtime

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Your code is compiled with debug flag enabled (/debug).

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Node.js 16.13.2.

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Your code is run with --harmony flag, enabling new ES6 features.

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lodash.js library is included by default.

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For Priority Queue / Queue data structures, you may use datastructures-js/priority-queue and datastructures-js/queue.

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Ruby 3.1

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Swift 5.5.2.

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Go 1.17.6.

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Python 3.10.

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With bcmath module

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