Find longest unique-character substring
Company: Snowflake
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: Medium
Interview Round: Onsite
Given a string s, return the length of the longest substring without repeating characters. Explain and implement an O(n) sliding-window solution using a hash map or set. Discuss time and space complexity, and note any changes needed to correctly handle Unicode characters.
Quick Answer: This question evaluates proficiency in string manipulation, use of associative data structures (hash maps/sets), and algorithmic thinking for detecting and maintaining unique-character substrings.