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  2. 2 Additional Online Test (If Required)
  3. 3 Office Interview with Hiring Manager
  4. 4 Unpaid Test Task (Motivation Check)
  5. 5 Paid Test Task and Follow-Up Interview
  6. 6 Iterative Paid Test Tasks
  7. 7 Office Verification
  8. 8 Final Interview with the Founder

Problems > Most Frequent in a Slice > Editorial

Most Frequent in a Slice — Solution & Editorial

Back to the Problem

Range mode has no easy prefix structure; the intended solution is Mo's algorithm (sort queries by √-blocks, maintain a frequency map and a bucketed max). At the provided sizes, counting each queried slice is acceptable.

Complexity: O((N + Q)√N) with Mo's algorithm