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 > Three in a Line > Editorial

Three in a Line — Solution & Editorial

Back to the Problem

Cross product of the two difference vectors is zero exactly on collinearity — integer-exact, no slopes, no division.

Complexity: O(1)

Watch out: Slope comparison divides by zero on vertical lines and rounds off at 109; the cross product does neither.