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 > One Swap Away > Editorial

One Swap Away — Solution & Editorial

Back to the Problem

Compare with the sorted copy: zero mismatching positions means already sorted; exactly two means test that one swap; anything else is impossible.

Complexity: O(N log N)

Watch out: Duplicates make 'find the two bad positions by scanning' fragile — comparing against the sorted array is robust.