Amazon, Microsoft, and Netflix ask this frequently. It's the canonical sliding window problem. If you can solve this, you can solve most sliding window variations. The pattern applies to dozens of problems: longest substring with at most K distinct characters, minimum window substring, longest repeating character replacement. Interviewers may ask: "What if we want exactly K unique characters?" or "What if we're looking for a specific pattern?" These are all sliding window variations.
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$ curl repovive.com/roadmaps/maang-interview-prep/two-pointers-sliding-window/longest-substring-without-repeating-why-this-problem
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