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 > Flips to Alternate > Editorial

Flips to Alternate — Solution & Editorial

Back to the Problem

Only two alternating targets exist: 0101... and 1010.... Count mismatches against one; the other costs |S| minus that. Take the minimum.

Complexity: O(|S|)

Watch out: Greedy local fixes can get stuck — comparing against both global patterns cannot.