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 > Stacking Hexagons > Editorial

Stacking Hexagons — Solution & Editorial

Back to the Problem

Sum k(2k−1) using the square-sum and triangular formulas; the result is K(K+1)(4K−1)/6.

Complexity: O(1)