Skip to content
Hiring process8 levels
  1. 1 IQ Test
  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 > How Many Times Does X Appear > Editorial

How Many Times Does X Appear — Solution & Editorial

Build a frequency hash map once; each query is a lookup.

Complexity: O(N + Q)