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Longest Substring No Repeat

Python data engineering interview problem. Difficulty: intermediate. Pattern: Sliding Window. About 14 minutes. Part of the Pro drill bank.

Length of longest substring with all unique characters. Treat this as a production helper: match the contracted return shape, including empty and duplicate inputs.

Implement length_of_longest_substring(s: str) -> int. ("abc").

Requirements

  • Max unique-character substring length.

Constraints

  • ASCII characters.

Examples

Input: length_of_longest_substring('abcabcbb') Output: 3 abc is the longest unique window.

Topics: lakebench, python, window, unique.

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intermediate

Longest Substring No Repeat

Interview-style drill: Length of longest substring with all unique characters.

Implement `length_of_longest_substring(s: str) -> int`. Example: `"abcabcbb"` → `3` (`"abc"`). Keep the harness.