Longest Subsequence Repeated k Times
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.
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.
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.
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.
Example 1
Input
s = "letsleetcode", k = 2Output
"let"There are two longest subsequences repeated 2 times, "let" and "ete", and "let" is the lexicographically largest one.
Example 2
Input
s = "bb", k = 2Output
"b"The longest subsequence repeated 2 times is "b".
Constraints
- n == s.length
- 2 <= k <= 2000
- 2 <= n < min(2001, k * 8)
- s consists of lowercase English letters.