• # For Solution

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`.

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.

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.

• For example, `"bba"` is repeated `2` times in the string `"bababcba"`, because the string `"bbabba"`, constructed by concatenating `"bba"` `2` times, is a subsequence of the string `"bababcba"`.

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.

Longest Subsequence Repeated k Times solution leetcode

```Input: s = "letsleetcode", k = 2
Output: "let"
Explanation: There are two longest subsequences repeated 2 times: "let" and "ete".
"let" is the lexicographically largest one.
```

Longest Subsequence Repeated k Times solution leetcode

```Input: s = "bb", k = 2
Output: "b"
Explanation: The longest subsequence repeated 2 times is "b".
```

Longest Subsequence Repeated k Times solution leetcode

```Input: s = "ab", k = 2
Output: ""
Explanation: There is no subsequence repeated 2 times. Empty string is returned.
```

Longest Subsequence Repeated k Times solution leetcode

```Input: s = "bbabbabbbbabaababab", k = 3
Output: "bbbb"
Explanation: The longest subsequence "bbbb" is repeated 3 times in "bbabbabbbbabaababab".
```

Constraints:

• `n == s.length`
• `2 <= k <= 2000`
• `2 <= n < k * 8`
• `s` consists of lowercase English letters.