Sliding Window: No Repeats | Dataford Interview Questions

Given a string of characters, find the largest substring with no repeating characters.

Implement longest_unique_substring(s) and return the substring itself. If multiple substrings have the maximum length, return the one that appears first. The input may contain letters, digits, symbols, spaces, or Unicode characters.

Function signature: def longest_unique_substring(s):

Input: A string s.

Output: The longest substring containing no repeated characters. Return an empty string when s is empty.

Constraints

0 <= len(s) <= 1000
The input may contain any Unicode characters
The returned substring must preserve the original character order
If several answers have the same maximum length, return the earliest one

Function Signature

def longest_unique_substring(s):

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