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 > Decode the Message > Editorial

Decode the Message — Solution & Editorial

Back to the Problem

DP over positions: extend by a single non-zero digit, or by a two-digit value in [10, 26]. Zeros are the trap — a 0 must attach to a preceding 1 or 2.

Complexity: O(N)

Watch out: Strings like 100 have zero decodings; every 0 needs a valid two-digit partner.