How we define and rank instructor expertise
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              Academic & research: CS degrees, algorithms coursework, publications, or problem-setting experience.
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              Industry leadership: big-tech interview prep pedigree, shipped systems, design reviews, OSS libraries.
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              Teaching & communication: years teaching DSA, student outcomes, clarity, and reviews.
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              Verification: we cross-check instructors via official course pages and the LinkedIn/GitHub profiles listed on each card.
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              Weighting: Academic/Research 40%, Industry 35%, Teaching 25%.