Meet Allison & Tim
Your AI coaches
Practice coding interviews out loud with real-time voice coaching. Your code actually runs.
Start Part 1 to unlock your next challenge
Climbing Stairs
Count the ways to reach the top when you can take 1 or 2 steps at a time. It looks like a brute-force recursion problem, but it's actually your first real dynamic programming question. Once you see the Fibonacci pattern hiding inside, a whole category of DP problems clicks into place.
Meet Allison & Tim
Your AI coaches
Practice coding interviews out loud with real-time voice coaching. Your code actually runs.
Desktop required to run this problem
StrongYes runs real code + tests in a desktop editor. Mobile is view-only for now, so you can’t start this here. Sorry about that — email yourself a link and pick it up on your computer.
Start Part 1 to unlock your next challenge
Desktop required
Sorry — mobile can’t run the editor + tests yet. Email yourself a link to continue on desktop.