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 > The K-th One, Under Fire > Editorial

The K-th One, Under Fire — Solution & Editorial

Back to the Problem

A Fenwick tree over the bits gives prefix-counts of ones; the k-th one is found by binary searching the prefix count (or by descending the Fenwick tree in O(log N)).

Complexity: O((N + Q) log N) (log² with plain binary search — also fine)