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 > XOR of 1..N > Editorial

XOR of 1..N — Solution & Editorial

Back to the Problem

The prefix XOR is periodic with period 4: it equals N, 1, N+1, 0 for N ≡ 0, 1, 2, 3 (mod 4).

Complexity: O(1)