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Md Ariful Haque @mah-shamim

The K-th Lexicographical String Of All Happy Strings Of Length N

Generate all happy strings of length n in lexicographical order and return the k-th string. Use backtracking to build strings character by character, ensuring each new char is different from the previous one.

1415. The k-th Lexicographical String of All Happy Strings of Length n
Difficulty: Medium
Topics: String, Backtracking
A happy string is a string that:

consists only of letters of the set ['a', 'b', 'c'].
s[i] != s[i + 1] for all values of i from 1 to s.length - 1 (string is 1-indexed).

For example, strings "abc", "ac", "b" and "abcbabcbcb" are all happy strings and strings "aa", "baa" and "ababbc" are not happy strings.
Given two integers n and k, consider a list of all happy strings of length n sorted in lexicographical order.
Return the kth string of this list or return an empty string if...