The general case I handled fine, grouped by student id, sorted each group descending, sliced the top three.
Start by clarifying the problem: group records by student, sort each group's scores descending, and take the top three. For the general case, use a hash map to group and a min-heap of size 3 per student (or sort each group). For the optimized case with integer scores 0-100, use counting sort or a fixed-size array per student to achieve O(n) time.
Pro tip: Explicitly discuss tie handling (e.g., if multiple students have the same score, keep all or pick arbitrarily) and how to handle students with fewer than three scores (return all available). Also, mention that the optimized solution uses O(1) extra space per student due to the bounded score range.
Ask about tie-breaking rules, output format (e.g., list of scores per student), and whether students with fewer than three scores should be included. Confirm that scores are integers between 0 and 100 for the optimized case.
Use a hash map to group scores by student_id. For each student, sort the scores in descending order and take the first three. Complexity: O(n log n) time due to sorting, O(n) space.
Since scores are integers 0-100, use a fixed-size array (size 101) per student to count occurrences. Then iterate from 100 down to 0, collecting scores until three are found. This yields O(n) time and O(1) extra space per student (or O(k) for k students).
If ties occur, decide whether to include all tied scores or limit to three. For students with fewer than three scores, return all their scores in descending order. Ensure the output format is clear.
Compare the general and optimized solutions: the general approach is simpler but O(n log n); the optimized approach is O(n) but uses more memory per student (though bounded). Discuss when each is preferable.
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