How to Solve Longest Nice Substring Problem
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Longest Nice Substring
A string s is nice if, for every letter of the alphabet that s contains, it appears both in uppercase and lowercase. For example, "abABB" is nice because 'A' and 'a' appear, and 'B' and 'b' appear. Ho...
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Understanding the Longest Nice Substring Problem
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Problem Statement
A string s is nice if, for every letter of the alphabet that s contains, it appears both in uppercase and lowercase. For example, "abABB" is nice because 'A' and 'a' appear, and 'B' and 'b' appear. However, "abA" is not because 'b' appears, but 'B' does not. Given a string s, return the longest substring of s that is nice. If there are multiple, return the substring of the earliest occurrence. If there are none, return an empty string.
Longest Nice Substring
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Examples
s = "YazaAay""aAa""aAa" is a nice string because 'A/a' is the only letter of the alphabet in s, and both 'A' and 'a' appear. "aAa" is the longest nice substring.
s = "Bb""Bb""Bb" is a nice string because both 'B' and 'b' appear. The whole string is a substring.
s = "c"""There are no nice substrings.
Constraints
1 <= s.length <= 100s consists of uppercase and lowercase English letters.How Interview Coder Helps with Leetcode Problems
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